Bluffing or Not Bluffing (limit or No Limit)

Couldn't agree more. My father always advised there was no shame in being bluffed out of a pot. Much worse to lose much of your stack on a marginal hand hoping the other guy is bluffing.

If you are allowing your instincts to make this decision for you, you are making a mistake. In a live game, look at your players mannerisms. In an online game, look at their betting patterns. I limp/call preflop, I sit and hesitate a call on the flop, a seemingly harmless card comes on the turn and I go all in as soon as the action's on me? I just made a big hand, or a crazy bluff.

How many times have you seen me do that? How likely is your hand to improve? Did I go all in because I wanted you to call or because I wanted you to fold - I won't lie - I'll go all-in with the dead nuts if I think it will make potential draws fold. And I'll be scared when I do it, too. Not because I'm afraid you'll call, but because I'm afraid you'll catch up.

But I'm guessing by the vagueness of the thread, this will not be a serious discussion about the bluff, and I've just wasted 300 words.

If you want to discuss the topic seriously, I'd re-phrase it - under what circumstances does it make sense to call a river bet light. There are certainly good situations to do so.

As a general rule though, if you don't have a good reason to call down light, you probably shouldn't, which I think is the point OP is making.

If your opponent's not bluffing when you think they are, sounds like a problem with hand reading or tilt issues.