Gratitude. Apparently it's not something that people can be taught to have, and I tend to get bent out of shape about it. When someone does something for you, no matter how grudgingly it is done, or even if they are just doing it to not seem like 'that asshole who didn't even bother', you should just suck it up and be grateful that they did whatever it was for you at all. I'm not even joking. If I go out of my way to do something for you, appreciate it. I could have just as easily not bothered, and then where would you be? When someone feels unappreciated, the likelihood of them ever wanting to do anything for you (no matter how small or insignificant a thing) is not very high. For instance, if I go through trouble to show up at your stupid, out-of-town bachelorette party for a night (where I end up sleeping on a COUCH), do NOT get mad when I have to leave early the next day and ask "what's so important that you have to do on a Sunday anyway?". Show me some fucking gratitude because I came to a 'party' where all anyone did was talk about babies all night. That is a lot for me to put up with.
So yeah... gratitude. Grow some already.