Just like you and I (Grischuk-Karpov)
I watched the clip below - it's a game between GMs Grischuk and Karpov - and they do the same things we do: Decide to make a move and then reconsider while the hand is out to touch a piece; Blunder away pieces; Look for a square to place a piece after they have already touched it (the piece); and last but not least, they play great Chess like the rest of us!
So when you make mistakes, or you have doubts, remember that even the greats go through similar emotions/experiences/episodes...
Needless to say this seems to be a speed/blitz Chess game. You may need to watch it a couple of times to really enjoy it. Have fun!