I don't. I'm frequently a dick, unfortunately for those around me.
I don't. I'm frequently a dick, but the jerks around me don't deserve any better from me.
I don't. I'm sometimes a dick. Life can be hard, and sometimes that shows through my temperment.
I don't. I'm really nice, I think, but the people around me don't see it that way and think I'm a jerk.
I manage by remembering that we're all in the same boat / I remember the golden rule.
I manage by considering the negative consequences (for me or for others) of me being a dick.
I manage by relaxation / meditation / therapy / drugs / some other method of catharsis.
I manage naturally, intuitively. It's not all that difficult for me.
I manage by drinking the magical blood of virgin space onleys. Mmm. Bacon-y.
Other: some other anwser? Put it in the comments!