I only show my cards in a few specific situations. The first one is when I’m in the big blind and everyone folds, and I happened to have a premium hand. There’s no real strategic reason behind it, I just do it for fun and to laugh a bit about not getting the chance to play a strong hand.
The second situation is after a well-executed bluff, although I don’t do this very often. I usually prefer to leave my opponents guessing, since showing a bluff is basically giving away free information.
The third case, and the only one where I think it can actually have some value, is in tournaments when everyone is short-stacked and I go all in to steal with a marginal hand, like K5. Sometimes I show the king to make opponents think I might have had a stronger hand than I actually did.
Overall, I don’t think showing cards is very useful. In most bluff situations, it just gives information away, and against good players it doesn’t really change how they play, it only shows that you’re capable of taking certain risks.