Have you ever experienced it? You have the better cards and the opponent called every raise? And in the end, it's the damn coincidence that decides again?
Yeah it happens a lot. People call with weak hands and sometimes hit something on the river. It’s frustrating but that’s why these games are profitable. If they keep calling too wide I just keep betting my strong hands and let the math do the work.
It's just variance, can't expect to win all the time, fish are going to chase and win sometimes, there will be more wins coming from you in the long run
Its rare to have your opponents drawing dead before the river, so thats just part of the game. The important is to not lose to much, when for instance your overpair is no longer good.
Yes, it happens that the opponent follows big bets with “bad” cards and in the end wins, which is really irritating. One should be prepared and accept such a situation as normal.
If there is a chance it can happen in poker, it will happen in poker. The longer you play this game the more you will see it. So you just get used to it and be ready to move on after it happens to you. Remember that we also get lucky on the river so it comes around and goes around. Good luck!