Wait... there are times a nap isn't necessary?
I'm an incredibly lazy person but just can't get into napping. Unless I'm really tired, I tend to wake up groggy and tired after a nap (maybe I'm doing it wrong lol). So if I'm a little tired, I'll get up and do something to get blood moving and oxygen flowing to my brain.
It's probably because I get enough sleep (7-8 hours) most of the time so I'm never running a sleep deficit. Mrs. RoG, on the other hand, is a master at napping but that might have more to do with slight anemia (or at least she blames it on a medical-ish condition ;) ).