From what I understand from poker rules, It seems possible to intentionally muck the best hand. It seems unlikely as it would mean losing money... but could be some way to trick an opponent into being overconfident. Is there any example of someone doing that and it having some significant influence (allowing to recoup his /her loss or more) ?
The only situation I could think of where a player would gain from mucking a winning hand is collusion (cheating). For example, player A and player B join a tournament and they decide that they are both going to work together to help player B win. Player A, B, and a third player C get into a big pot and player A is betting very large. Player B calls the bets and so does player C. Player A is inflating the pot so player C puts more money into it, and if player C folds/loses player B will win the hand because player A mucks no matter what.
The definition of mucking a hand is to discard a hand, meaning the hand is conceded and is no longer in play. While there are circumstances where a hand can be retrieved from the muck, if a player releases their hand, IE folds their hand it is a done deal. (if the hand was not conceded by the player, the dealer accidentally mucking, some other player tossing it into the muck etc. it may be retrieved from the muck)
I draw a blank as to this comment:
but could be some way to trick an opponent into being overconfident.
To boil this down to an answer, there is no possible way to gain an advantage by mucking the best hand.
Under tournament rules, a player who folds (or even checks down in last position) the best possible hand after all the cards have been dealt is assumed to be cheating, playing for someone else's benefit. There is generally no such rule in live play, but I would certainly penalize a player for doing that.
Of course before all the cards are dealt, it's quite possible that folding the current best possible hand is the right play. For example, I remember a hand of Omaha/8 I played a while back: I was in the small blind and called (after 4 callers) with 8s9s9hTd. The flop came down 6d7d8c. I checked, and by the time the action got back to me it was 4 bets. I folded. Yes, it's the current nuts, but I've probably got a negative EV.