When you go for a ride in a lighweight turbo early car, get sucked back in the seat during the rapid acceleration from 20-50mph (in city traffic) and spend the rest of the weekend pretending your Jeep Cherokee Sport is a manual trans p-car.
Or
When you start driving your Cherokee like it's a sports car, and then realise that it is, in fact, not a manual, but an auto, and it sits up a considerable bit higher than a P-car. But, IMHO, it puts the 'Sport' in Sport Utility!
Also when you check here and your email every hour, sometimes more than that, to see if anyone has replied to your posts when you should be doing something much more worthwhile, like studying for a midterm...