One of the meditation principles I find most valuable is the idea of non-attachment, or letting go. From BuddhaNet:
Let go of your clinging. Let go of the motivating desire behind whatever you're doing. It may be a desire to succeed, to be perfect, to control others or to glorify yourself. It doesn't matter what it is specifically; what matters is the desire behind your act. It is easy to mistake the act for the desire.
In meditation classes, I heard: Let go a little, and you'll have a little freedom. Let go more, and you will have more freedom. Let go totally, and you will have complete freedom.
I'm a clinger. I cling to ideas of what others should be -- in relation to me as well as in life itself -- and the way that the world should be. I cling to ideas of how my day should go, and heaven help the person or thing that interrupts my self-imposed schedule.
I rationalize the clinging as not letting people get away with things -- they can't treat me like that, can they? But it's not about them. It's about me and my reactions to them. Letting go doesn't hurt. It's not enabling. It's freeing.