Sky Color Feynman recounted another good one upperclassmen would use on freshmen physics students: When you look at words in a mirror, how come they're reversed left to right but not top to bottom? What's special about the horizontal axis?
Internal Monologue Oh right, eye contact. Ok, good, holding the eye contact ... holding ... still holding ... ok, too long! Getting weird! Quick, look thoughtfully into space and nod. Oh, dammit, said 'yeah' again!
Another thing that is a bad problem is if you're flying toward space and the parts start to fall off your space car in the wrong order. If that happens, it means you won't go to space today, or maybe ever.