I had somewhat of an opposite experience - while instructing in a far away land (about 15 years ago), I had a trial lesson where the prospective student explained that he flew model aircraft, knew everything about light aircraft and could fly "one of these little things" without any instruction. He assured me he could take off and land and really didn't need me there for anything.
I demonstrated the preflight, startup, taxi and runup and he tried to make it clear to me that I was wasting my time explaining this to him - he knew it all already...
I tried to explain the takeoff procedure (C-172) but he really wasn't interested (you've guessed it - already knew how to take off). I lined us up on the runway (5,000 feet long, 100 feet wide) and told him that he would be handling the controls (just the yoke - I did the power and pedals).
We started rolling down the runway, his hands confidently on the yoke and my right hand surreptitiously resting on my right knee when, suddenly, at about 50 kts, he recoiled into the fetal position screaming "oh my G-d, you take it...."
I climed up to about 2,500 and slowly re-introducted him to the controls - funnily enough, he was slightly less arrogant.