This one is quick.  I sometimes notice folks shaking their head when performing the WOD.  Guess what that does?  Creates negative energy.  You are physically saying to yourself “no”.  Instead, how about turning that around with a more positive approach.   Instead of the cheesy “yes, I can”, say “Let’s see what I got” or “Let’s see what I can do”.  Be more positive with your actions and thoughts and I bet it turns into a more positive performance.