Self-Acceptance or Self-Improvement?
Some people take self-acceptance to mean "if I have an urge to say asshole things, I should let myself be an asshole and embrace my assholery in full." That's a very shallow understanding of self-acceptance. Self-acceptance is a psychological shift that happens when you forgive yourself for all the way you fail to measure up to your own--and others'--expectations.
Most of our expectations are held in secret. They're so subtle that you don't even realize how pervasive they are. It's like air: it's everywhere, so you don't notice it unless someone points it out. Expectations drive all of our self-improvement efforts, and all our self-management efforts. When you meditate because you don't like some aspect of your current experience or think there's something missing, you're dealing with self-acceptance. You're rejecting the part of your experience (and the part of you) you can't look at. It's what Jung meant when he was talking about the Shadow as a personality construct.
When you accept the way you feel and the chaos and confusion in your life and all the ways this moment might be missing something, you lose the urge to fight. You lose the urge to be an asshole. You see how it is and you figure out, very immediately, what's valuable in life and what you need to do--your mission. In other words, you take a big leap towards self-improvement.