When you see a good move, look for a better one
One of the downside of a blitz game is that you cannot possibly hope to play the strongest moves every turn. There just isn't enough time for it. If it's a decent move, let alone a pretty good move, you better play it or you're going to burn unnecessary clock time.
I just played a 10/0 blitz game, where I was worse out of the opening, but due to my opponent's tactical oversight, I was in a very good position. But due to my mentality of "when you see a good move, play it" instead of the good old Lasker's advice "when you see a good move, look for a better one", I missed many chances to seal the game right away.
and later in the game...
and last but not least...
Obviously, the time factor contributed to me missing these easy winning moves. If this was a long time control match, I probably would have found those moves.
But time factors aside, one thing that also contributed is the tunnel vision mentality. I had a goal of promoting the pawn to a Queen on the last diagram. So I did not even think about checkmating possibilities. I did not take into account that the sublties of the position can change from move to move and allow new and better possibilities than your planned moves.