Why do i never see my oppenent has mate

This one is 10000000 times worse

Do plenty of mating puzzles and calculate what is possible in any positions. Look at your opponent's plans and make sure that you can either ignore their threats or need to defend against them.

I found that one thing that helped me see mates and tactics is to flip the board before I try to solve a tactics puzzle. I guess normally we see tactics from the side which is trying to execute the tactic; I thought about flipping the board and soving the puzzle from the perspective of the other player. This has helped me to see tactics "coming at me" so to speak. Something like that might help.

EDIT: Haha, puzzle didn't come out right.

Why wouldn't Qc1+ work?

Look for and pay attention to what is attacking and defending each pawn and piece on the board and what checks are available in every position. If you don't look you might not see.