In any industry, but especially in the creative industries, any professional will have many working relationships. When it comes to both getting work and having good working experiences how you manage those relationships is as important as your craft -- sometimes more so.
Since everyone makes mistakes, sometimes you will accidentally burn a bridge (especially if you misread what kind of a person you're dealing with, and what kind of a relationship you have). Some burnt bridges can be repaired, some can't, but the goal is to absolutely minimize bridge burning and absolutely maximize the number of people who are glad to know you -- even if many of those relationships never "amount to anything".
And it often may not amount to anything, because you can't enter into relationships with the expectation that there will be some kind of "payoff". You have to look at each relationship through the "it's just nice to know people" lens and let anything else emerge naturally. Of course you can and will ask for favors, and expect favors to be asked of you, but you have to know how, what and when.
Immediately after meeting someone is not the time to ask for a favor, but it can be the time to offer one. If you have something to give someone, and you're genuinely willing to give it without expectation of any return, then it's always nice to offer to help. Good karma accrued by being a helpful person is a reward in and of itself.
The time to ask for a favor is when you've known someone long enough that they can reassure themselves that you didn't befriend them just to ask for favors. How long that is depends on the individual, and if you aren't sure if it's time -- it's not. You don't know someone well enough if you don't know whether or not they'd be cool with you asking them for a favor.
What you can ask for depends on the closeness of the relationship, and is also individual. How you ask should always be "politely", and if you have something to offer in return it can be nice to do so. That may feel like "bartering" (and can offend some people), but I think it's just decent to offer a person something you know or believe can help them when asking them to help you.
It's also important to understand what kind of a relationship you've got with someone. Not everyone you work with will be a friend. A professional doesn't need to like someone at all in order to work with them. All that is necessary is being able to be professional with each other. If civility and actually accomplishing the task at hand isn't possible, then there's no way to work together -- but "like" is not a requirement.
Another thing that's important to understand, particularly in the entertainment industry, is that sometimes people will not respond when you reach out to them (even for a simple thing like hanging out). Assuming you had any kind of relationship with the person in the first place, there are three primary reasons for this:
They're too busy. In Hollywood especially, busy people just ignore anyone who (a) isn't in the immediate job queue or (b) too important to ignore. It's not a reflection on you (except how much of a power broker you are), it's just how things are. It's also best (for your own ego) to assume this is the reason, and reach out periodically (with decreasing periodicity) and try again.
They don't like giving bad news. Some people don't like to give rejections (bad news for you), or admit to difficulties (bad news for them), and prefer to leave people hanging instead. It's a bit rude and not especially helpful, but is quite common. But look at the upside: since they didn't give you an outright rejection, you can simply ignore the hanging topic and consider future conversations unencumbered by it if that's to your advantage.
They don't want to have anything to do with you anymore. It's sad but true, but sometimes you wear out your welcome with someone. Usually it's because you tried to enter into business dealing with them and they didn't like your concept / material / offer. But sometimes it's just because people change. The downside is that's kind of depressing, the upside is that since they didn't tell you to eff off, the relationship may re-kindle when one or both of your circumstances change.
It's also important to understand what kind of relationship you have with someone so you can know what to ask for, what to give, and how to deal with the cold shoulder (quick answer: unless there is a friendship, partnership or immediate deadline at stake don't push; try to reengage infrequently, and always be gentle about it).
Much relationship drama comes from one or both parties failing to understand what the true nature of the relationship is (or just being a jerk), and either asking too much or giving too little.
In your working life you will have several kinds of relationships:
"PARTNER"
A partner is someone -- who may or may not otherwise be a friend -- that you can work closely with because you have complimentary abilities, styles, and work ethics, and are able to develop the rapport necessary to both feed off each other's good ideas and be honest about each other's bad ones. Partners are committed to a collaboration, and within the context of that collaboration can be relied upon to support each other completely.
Partners need to be able to exchange deep, sustained and sometimes harsh critique, and maintain a harmonious, productive relationship. A partner can tell you that your idea or implementation is terrible, flat-out, and have it not be a big deal. Someone who can't be open and honest with you is not a partner, period, end of story.
Because nobody is perfect, and in fact most people (even the successful ones) make more mistakes than not. Successful people are just good at fixing them before its too late, and a successful partnership is one where the partners can help each other find and fix problems before its too late. Partners don't judge each other's bad ideas or bad material as a fatal flaw, but rather see it as part of a refinement process that leads from bad to great.
To develop that critical rapport partners need to both respect each other's abilities and have compatible styles so that a shared vision is possible, and the critiques can be additive and not dismissive.
"FRIEND"
A friend is someone you care about, that you can trust, that you can confide in, and who has already factored-in your most irritating regular traits and has decided they care about, trust and can confide in you despite your flaws. They're also someone you enjoy spending time with outside a work context (often exclusively), based on other shared interests. You can ask a friend for almost any favor at almost any time, and they expect to be able to do the same of you.
That said, you may not be able to work with a friend. Your styles may be incompatible, your friend may not have a good work ethic, or the ability to take criticism. Friends are utterly essential to being alive, but they are a mixed bag when it comes to working together.
However, people who say "never work with friends" are usually the ones who aren't very good at figuring out which friends can and can't become partners.
"COLLEAGUE"
A colleague is someone that you can work with, and work with well, but not necessarily initimately. In fact, you may work with colleagues often but not intimately. They are people you can rely on to get a job done, and that's about it (but that's a lot, so don't knock it).
Colleagues respect each other's contributions, and can exchange immediate critique so long as sensitivities are considered and decorum is maintained. A good colleague is someone you can depend on to get a job done, whose presence on your team is additive, and that you have a relatively stress-free time dealing with on an interpersonal level. (A bad colleague is "someone you put up with".)
A lot of colleagues maintain a facade of friendship, which is perfectly appropriate so long as you know the difference between "friendly" and "friend" and can determine which are your real friendships -- otherwise you'll inadvertently care, trust or confide in a colleague more than the relationship can support. Most of the people you have working relationships with will be colleagues, and a boss is a form of colleague (or of "someone you put up with") that merely has more authority than you do.
"CONTACT"
A contact is someone you have an infrequent, casual relationship with, or with whom it is clear the relationship is exclusively one that can be activated when mutual benefit can be had from doing so. You may like a contact more than you do some colleagues (and almost certainly more than most people you put up with) -- but they are not someone you can rely on to get work done or provide any other kind of support -- unless there is a clear, direct and immediate benefit to them in doing so.
"ACQUAINTANCE"
An acquaintance is someone who might become a friend or partner one day, but the relationship is new (or is slow growing) and therefore, despite the mutual interest, there's not enough trust, confidence and caring to sustain friendship or partner level interactions. An acquaintence may help you out, and you may help them out, but it will be minor, infrequent, or both.
"SOMEONE YOU PUT UP WITH"
A true professional does not need to like someone, enjoy working with them or even respect them in order to maintain a working relationship with them. They might even do work you consider poor quality, but someone else doesn't and as a result you need to just find a way to fill-in their gaps and make it work. This may sound like being dishonest, but it's only dishonest if you lie to them about liking them, enjoying working with them or respecting them.
There are plenty of ways to be civil, professional and even cordial to someone you put up with that don't require you to lie about how you feel about them. Simply avoid discussing the matter -- the vast, vast majority of people will never ask. If they do ask, you then need to decide if you should lie or tell a varnished truth such as "I find working with you challenging, but we're getting things done so apparently we're both up to the challenge". You can even give them pragmatic and civil critique about tasks at hand so long as you omit the ire you may be feeling.
Being able to truly put up with people you don't really mesh with very well is an excellent skill to develop -- it will afford you more opportunities, earn you a reputation of being "easy to work with", and enable you to be less miserable. It is the hardest relationship skill to master, the easiest to slip-up on, and not the most rewarding (being a good partner is the most rewarding) -- but it is worth putting effort into all the same.
Over time, people you have relationships with may change categories. You hope that every relationship will always be moving towards a more intimate category, but that is just not the case. Different personalities and circumstances mean that the shifts may be in either direction, at any time, and with varying intensities of emotion surrounding them. To be someone who is "good to work with" you need to do your best to roll with those changes, and continually monitor your relationships to make sure you're behaving appropriately with regards to that person's current status.
If you do inadvertently create relationship drama by asking too much, giving too little, or just generally doing something insensitive -- apologize. Sincerely, not a mere "mea culpa", meaning that you took the time to identify exactly what you did, figure out why it was inappropriate, understand how it rankled the other person, and then conveyed that in an appropriate way.
And if that doesn't work, the relationship may soon become a non-working relationship. There are indeed various categories of non-working relationships, but the only parameter of a non-working relationship that actually matters is the answer to the question "is it salvageable?" If the answer is yes, then wait an appropriate amount of time and reengage. If the answer is no, move on.
Finally, if this makes working relationships seem very one-sided, remember that the only person you can control is you, and that the other half of every relationship you have is supposed to be endeavoring to be "good to work with" as well. If they do not then that's their problem, not yours.