I have gone all-in on many different hands, from pocket pairs to suited 2 gappers, even off suit connectors. There are also many reasons for going all-in-
1) The pot has got so bloated from raise's and re-raise's, you really don't want to battle it out with 3 or 4 callers, with Pocket Aces.
2) If you make a raise from any position and someone 3X bets you, you are suddenly put in a position where you have to decide whether to just call, fold, or shove All-in. Going all-in pre-flop before that happens puts your opponent in that position.
3) If your chip-stack is getting low you can steal the blinds, or even double up if your all-in is successful, either way a win is a win.
You will be forced at some point in every game to go all-in, whether because you are short on chips, or your opponent is, really does not matter, the important thing is winning that one crucial hand, and from my experience any 2 cards can win on the River. I recently watched a heads up in a
wsop event where the chip leader shoved all-in with 10/Jack of spades, and the opponent called with a 3/4 off suit the 3/4 won by pairing the 3 on the River, which proves any 2 cards can and do win.
I have in some games folded QQ when 2 players before me have gone all-in, especially close to the bubble or a money ladder, in other situations I have called 3 All-in players with Pocket 8s guessing correctly that they are all playing an Ace rag hands, but having a chip lead over them it was an easy call that would have cost me half my stack if I had lost. At the end of the day you really have to follow your gut! As the saying goes "No guts! No Glory!"