In Fallout 3, I would often stand in a corner and throw frag grenades at the ground, or I would run up to the highest section of highway I could find and jump right the hell off. Back when I played Halo, I'd also hit my feet with a plasma grenade and run around yelling "Shiny SHOOOOEEEEES!" and had the joy of seeing myself explode on my friend's co-op screen.
I think this type of playing started because I had to impress my brother and sister when I was younger. I was the oldest of the three of us, and the only one who could handle the controls for games like Resident Evil, Megaman Legends, and Metal Gear Solid, so I had to do silly things to keep them interested - like setting 20 lbs. of C4 on a wall outside the Revolver Ocelot boss battle and blowing up every one of the endless, stupid guards that ran up to see what all the commotion was about.
Honestly, it's influenced my life so heavily, I couldn't imagine my gaming life without that perspective; some of my best memories in life are of those times with my siblings.