Unless it's a serious emergency, always start every interaction with another person by greeting them first no matter how brief the interaction might be.
Going up to, for example, a store employee or a co-worker and just blurting out a question or request you have for them without greeting them first can come across as you just see them as a means for getting what you want instead of seeing them as a human being first. If you just say even a simple little "hi" first (or whatever a standard greeting is in the local language might be) before asking them a question or asking them for help, you are acknowledging that they are a person instead of just a means to an end.
Based on my experience working in the tourism industry I should probably also point out that although "excuse me" is considered sufficient in some cultures, this isn't universal and in some cultures just saying "excuse me" first without any greeting word like "hi" or "hello" is considered rude.
So if you are from somewhere "excuse me" alone is sufficient, keep in mind that might not be the case when you're traveling, and you might come across as rude if you only say "excuse me" to get an employee's attention but nothing else while you're traveling.
I hope it's ok to riff on this a bit and add that starting with a greeting is also important on the phone, especially in the dreaded scenario of making a cold-call. I know my generation and forward do not like to make phone calls at all, but sometimes you simply have to, and if you do a good greeting, that's half the battle won. I have to make cold calls a lot at work and I've found that best practice is to begin any outgoing call you make by doing the following in this order:
Greet the person who answered (Hello, good afternoon, etc.)
State your name and your organization or relationship to the business or person you're calling.
If you're feeling friendly, ask the person who answered how they are doing or how their day is going.
Compare these two examples:
Answerer: Hello? Caller: Good afternoon, my name is scarylullabies, I'm a tumblr user, how are you doing today? Answerer: Fine thank you, how are you/how can I help you? Caller: I'm doing well, I'm calling to confirm the colors of the tile you'd like installed in the children's hospital...
vs
Answerer: Hello? Caller: Hi, can you confirm the colors of tile you'd like installed in the children's hospital?
One of these is way more abrupt, and with no context for who you are or why you're asking, it can really throw people off, even if the question is or seems innocuous and inconsequential to you.ย
I can't emphasize enough how much stress this greeting method has saved me. Starting calls this way makes the rest of the call a total breeze and has made it so much easier for me to handle my personal outgoing calls (for appointments and whatnot) as well.
