I remember when I was 11 years old and got to the final castle in SMB3 for the first time. I was so excited, and so nervous. So nervous, in fact, that I literally tiptoed over each square, terrified of what might be coming. As it turns out, tip-toeing is not the best strategy.
Somehow, though, I was able to avoid instant death. I just wish there were more surprises like this throughout the game.