Playing the Eye-Toy Kung-Fu game on my PS2, just after watching the film 'Shaolin vs. Wu-Tang' & whilst being under the influence of a drug usually reserved for horses.
I thought it would be look cooler to use a Tai-Chi sword, which it was, but I got so carried away with my mock Wu-Tang swordplay that I ended up with quite a few cuts on my back, shoulders & arms from where I was swinging the sword around my body looking cool, which I obviously didn't feel at the time.
The thing was, since I could see myself on the screen & in the game, beating all those little kung-fu dudes with my sword & increased muscle tension, I didn't just think I looked cool, I knew I looked cool.