I'm going to refuse to do a request for a friend because I had no time and no details for his request
Are there other reasons for refusing?
I lost my sense of friendship with them
I get that it can be frustrating that they didn't give you any details to work with when they should have. They are just taking advantage of you, and it's great you're refusing and reevaluating your relationship. It's not worth it if they're going to walk all over you.
Yeah, and if they ask again I'm going to get angry and yell at them if they ask me directly.
I think that might be an over reaction. I also don't like it when people are being cryptic. Maybe you can send them a text messages declining their request so they know and can find someone else.