What do you think about this...

Just wanted to whine a little.. Look at this.
My opponent gave me a perfect, glaring, obvious mate, but did I see it? Yes I did. Five seconds after hitting move! I will still win the game (probably), but come ON!
Game 1272466

And yes yes, I know it's in progress. I just wanted to discuss this type of mistake. I am, I guess, the only one here that would not see this mate. How does this happen?!

And I just now, while typing this post, I realize I could just have pinned his knight and all would have been well. I think I will give up playing chess... Well maybe not. But it's so frustrating.

The way to avoid missing mates in one is before every move, look at all possible moves you can make. Then once you've done that, pick the most interesting one and see what the opponent can do in response. This catches 99% of those mistakes.