The frustration of the Training Puzzles

If you get frustrated because of the stupid computer-generated puzzles on this site that you would never encounter in a real game and you know it, then I would say that YOU are completely normal!  Because almost ALL of the chess puzzles on this site are completely stupid!

Many of the puzzles probably will never be encountered in a game. At least not the exact position. But that's not important. Whats important is recognizing what makes the puzzle solvable. That is something you WILL encounter in almost every game. 

The really stupid puzzles on chess.com are placed there by members with free access to the Puzzle Forums. Most training puzzles provided by the chess.com crew are decent. Good training puzzles teach recognizing and handling tactical patterns, not precise game positions. A position may be completely unreal and still teach you the right lesson. Mohammed Ali jumped ropes and hula hooped for training even when these conditions never exactly arose during his ring fights!

Good topic

A very large portion of the puzzles come from actual games.

I get positions in games where I recognize tactical possibilities (themes) that I have previously seen in the puzzles here. I also miss some as well but are ones that are similar to puzzles here.

I think it would help a lot if it said if the goal of the puzzle is to checkmate, or capture a piece

You don't get hints in real games and do not even know there's something to find. There's benefit in knowing themes, and you can solve unrated by themes, but for a general puzzle, it's better for calculation and board awareness to figure it out.

I once knew a man who practiced golf more than anyone I had ever met. He practiced literally every day. But he was a terrible golfer.

Practice makes permanent. He spent all that time making sure he never got better by practicing the wrong way. Only perfect practice makes perfect.