When a teacher calls on you in class and you weren't expecting it and you automatically start to panic and you turn red and start sweating and your brain stops moving and your heart is beating too fast to be healthy and you know that since your brain isn't working that you won't be able to answer the question so you just kind of sit there for a minute and stall and say "I don't know" and then afterwards you kick yourself over and over and feel stupid for not saying the obvious answer and cringe about that moment every night for the rest of your life