Sometimes when something bothers you, you're the only one that knows. You'd sound pretty whiney if you spoke up every time someone unintentionally hurt your feelings, but if you see that it's a pattern, maybe it's time to speak up.
I get afraid when it comes to sharing how I feel about something. Sure, I don't have a problem asking for tangible things that I want. But when it comes to how I am being treated or how I feel about something, my first instinct is to keep quiet, pout to myself, and then try to move on. The problem here is when it happens again, and maybe even again, you start to get a little angry and worry that it might be intentional, even when rationally you know its not because you never spoke up in the first place.
So, when something bothers you, find the right time to speak up and explain why it makes you feel the way it does. It makes life a lot easier, since most people aren't very good mind readers.