So I've seen this a couple times while I was not in the hand, but this recently happened to me in a 1/2 game and I got bet out of a hand where I had a good pocket pair.
Hands starts like this: SB, BB, UTG1, UTG2, UTG3(ME)
UTG1 calls BB, UTG2 raises to 16$ I call, UTB1 calls and SB & BB fold, so 3 players in the hand (UTG1-3)
it's not really about the cards here so I won't be saying what was on board or anything. On the flop, UTG1 checks, UTG2 bets $25, comes to me -> I'm weighing the bet, I'm definitely calling but I'm looking to raise to maybe $75, I count out my chips into three $25 piles, as I do this I look at UTG1 and he is ready to fold as he is seeing me bet the $75. But I only call $25, UTG1 snap calls as well.
Turn now, without much thought, UTG1 takes a stack of chips, and bets, it was $130, UTG2 quickly folds and then on to me. I have a very good pocket pair, but I'm afraid two pair or low pocket pair that hit the trip on the turn, or possible straight or whatever. As I'm thinking for about 30 seconds, UTG1 grabs his cards, puts a dollar chip on top of the card as a tip to dealer and just waits for me and just hold it in his hand pointed it at the dealer. Now he is not obviously mucking the hand as there would be no point to put a dollar chip on it, he knows I'm gonna fold and I do like a dummy.
What does a behavior like that say about a player? That confidence - he didn't say much, just the fact that without even counting he bet 25% of his stack, then confidently was waiting for me to fold.