re: Poker & 10max - 99 vs river shove-very loose opponent
I dunno why he would be raising preflop from mid with A2, although that definitely doesn't mean he isn't doing that. On the flop he'd have a gut shot draw which people hate to fold for some reason.
With the preflop raise and calls, he could be a set of 8s, but he could also have an overpair, which is going to be bigger than yours. Or A5s gives him the straight on the turn.
Because he's shown bluffs is a reason to call. The size of the bet may indicate he's got a hand, but it may be just that the pot is bigger or he thinks you need a bigger bet to be bluffed. I'm mixed on whether the net consideration of that is a reason to call or not. But your check on the river might have been the inducement for him to bluff, his thinking being, I've got no hand, but he's afraid I have a trey of 2s so he'll fold to a bet. And if he's got A8s it makes him even more comfortable. Because of your leads previously, I think throwing out a blocking bet might have been a better play to minimize this thought pattern.
If he were a good or tight player, I'd fold this. But, all in all, I might lean towards a call, though I'd also guess that you folded and you're wondering if it was the right decision.