To your adult close friends - you can dish out the dirt over martinis and/or Haagen-Dazs.
In public, speak the truth, the truth, the truth! Or please don't speak.
To your adult children, you can take the conversation where they lead, or confide in them honestly but with deep consideration of the effects.
To your young/minor children, answer their questions honestly and openly, but do the same self-editting you'd do if you were on the phone in front of your 6 year old gabbing about how your boss is this or the feds or this or that neighbor are so @#$! annoying or whatever. You know you wouldn't go all Richard Pryor in front of a kid (I hope!!), nor would you want your bundle of joy to go about the neighborhood innocently repeating your words.
Imagine THOSE chance meetings while gardening or getting the mail....can we say "awwwwkwuurrrrd"!
Respect your children's feelings, and the fact that "daddy/mommy" may be a very different person than the mother@#$! who was selfish, unfaithful, "emotionally unavailable", a deadbeat - et cetera.
Save the bitching and mud-slinging for the bar stool...uh...unless you're in public office. Hell, there's a good chance that there's a handful at same bar scratching and/or stabbing backs!
Would you want to be seen in the same light as a sleazy politician? Right. So, take the high road.