"Should I talk to this person?"
This is a question that you ask yourself many times.
The vast majority of the time, the answer is no. There are many reasons for this that include but are not limited to:
This is an unsafe place to approach someone.
They've already told you to leave them alone.
You suspect that they're uncomfortable around you even if they haven't specifically mentioned it.
They're not at a place where they go to meet people.
They're busy doing something else or talking to someone else and talking to them now would be interrupting and rude.
You just talked to them a little while ago and talking to them now would be obsessive.
You know that you're welcome around them but you don't know if you're welcome around the group they're currently with.
You have nothing to say to them at the time, and trying to talk to them now would result in you just saying hi then standing there awkwardly silent or taking wild guesses at what to say and making the conversation feel forced.
You don't have the energy to socialize at the time.
But if you always answer no, then you're guaranteed to be alone forever.
So despite having to answer no the vast majority of the time, you also have to answer yes some of the time.
You ask others for help determining in what situations you should talk to people. They just tell you to talk to people. This doesn't help, because you're asking "How do I determine at which times the answer is yes and at which times the answer is no?" and they're just telling you "Yes."