Why do poker players angle-shoot?
The commenter says, don't good players want to avoid a confrontation with the opponent / floor and just keep their cards to themselves until someone says DEFINITIVELY that they're pushing / folding / checking? [...] I hear a lot of people tell stories like this, and they're either just barely over the line, or not-as-out-of-bounds as their opponent, but the fact remains that you don't want it to be YOUR fault when there's a situation like this.
Well, first off, good players want to rake in the chips. If you show me someone who doesn't shoot any angles, I'll show you someone who doesn't play poker. Angle shooting happens to be part of the game, and even the professionals utilize the rules to their favor. Jennifer Harman took a pot off Doyle when she tabled her hand and he mucked the winning hand, as noted in The Professor, the Banker, and the Suicide King. People will use the "string bet" rule to their favor when they don't want to pay big money to chase their draw, and Annie Duke is famous for wanting to allow Jim McManus to put in a string raise so that she can fold her A-rag and is livid when other players call it on Jim. I can't find the article, but what about the guy who looks down in the big blind, sees pocket aces, and says "I'm all-in. Just kidding, but I'm going to raise!" knowing full well that he's going to be called on it and the all-in will stand, but it could induce someone to call, thinking he's weak. The article actually talks about a professional player making this move, and says it's a move in the pro's playbook. But it's still angle-shooting, and that's just the tip of the iceberg.
Of course, the angles range from rule nit-picking (where I know I do angle shooting - I've called the clock on someone because I want them to fold), to annoying - like stalling when the bubble in a tournament comes close, to downright immoral (colluding, or cheating by sneaking on more chips than the max limit at the NL table would let you do), but I know people in all three categories - they all shoot angles. As a point of note, I don't condemn the immoral angle shooters, and in fact have gone off at them more than once when I find it out, and someone constantly shooting every rule-based angle gets on my nerves as well, but that is poker, and caveat emptor still is the default law in the card room, despite the clean up from the ol' wild west it used to be. YOU, the player, needs to be aware of what collusion looks like, what the rules are, and the like, so you can protect yourself, as well.
However, great players not only want to rake in the ships from the less-skilled players, but also want those players to have fun losing their money so they keep coming back and donating. In that sense, most great players stay towards the rule-based angles and try to do it as pleasantly as possible, especially when a whale is involved, because you don't want them getting pissed off to the point where they're going to take their ball and go home. But, in the case of the baby game at trump, it's really not as important, because when one guy gets up, there are 10 more waiting to take his place.