When I was a kid I found this awesome gift for someone that I only sorta knew and my mom responded with "Why would you do that? They aren't going to get you anything" but for me the act of gift giving has never been about what I'd get in return, it's about the act of giving someone something you know they'd like or that would make them happy.
I don't do nice things for people because I expect them to give back to me. I do nice things because I like to make people happy. Most of the time it's little things, helping them out, buying them a drink, making them food, whatever the case may be. I do it because sometimes all it takes is that one little show of appreciation, of thanks, of thoughtfulness that can make someone's whole day.
So take a minute to show your appreciation to those around you. Say thank you, get them a card, give them a hug, whatever it is that will make them happy. It doesn't take much effort and it really can make the difference in someone's day.