Whenever I see a car, or any form of transportation in front of me with the driver in it, I immediately imagine myself jacking their vehicle, punching the person in the mouth, them saying something stupid like "Hey I need that!" and then driving off into the sunset, just like GTA.
Or I picture me comandeering the vehicle Halo style, boot kicking their ass out of the seat, which would be especially effective to anyone on a motorcycle, and gunning it to the covenent base.
But nothing beats nightime, where I can't help crouch running like Snake through people's backyards, pretending I'm using my codec.