I never show.

I rarely show my cards, I only do it if I feel I can manipulate a villain's approach in future hands. Showing you fold AK tptk to a stupid open shove tells him that he can push me off tptk by open shoving. So maybe next time he thinks I have tptk he open shoves a wider range, making my tptk a much stronger hand.

Likewise, maybe I show a bluff because I think there's a good chance it will tilt villain into making mistakes.

I only show my hand if I have a good reason to.
When you do that you also give away information to the rest of the table... high price to pay to influence the play of a single villain imo.