I am a nice person. I grew up believing that doing good to others would benefit me in the long run. Sure, there is even an old saying that if you treat others well, they will also treat you well. But as I mingle with different people, I noticed that it's not necessarily going to happen. Sometimes, my being nice even made me into a doormat. I'd become an under appreciated, sad, cynical, and resentful person because of that.
But then I realized, in order to change how people treat me, I should change myself first. By voicing out my thoughts and feelings more often, other people would know what I want. This is called assertiveness. It is not being egotistical. It is not being aggressive. It is simply putting your own needs equal to others' needs. Tell people what you want, also listen to what they want, then reach for a resolution.