Doppelganger lays it out for the world over at 50 Books with her list of hard-won wisdom:
6. Saying whatever is on your mind all the time is neither "being true to yourself" nor is it "just being honest." It's "being an asshole."
There is no excuse to be a damn fool after reading her post.
The only thing I could possibly add to this list today is this:
_The nice, secluded stall you use at work to take big, nasty dumps in is the same one everybody takes big nasty dumps in. We all know what you are doing in there, even if we can't see your shoes, and I for one do not judge you.