Trying to have a guy in marketing explain a problem with his computer over the phone is like attempting to urinate with an erect penis. When working MIS help desk, asking the user to reboot can sate them through one of three methods.
First, rebooting gives the troubled user some time out to think through his or her issue. This oft brings about a convenient cloudburst of neural activity, as seemingly very little occurs before the impulsive dialing of yours truly. Grr...
Second, rebooting can actually solve difficulties on Windows boxes. Xyzzy!
And finally, users will sometimes shrug insignificant problems away when faced with the annoyance of waiting for a reboot. This is especially true in a large company full of bitty boxes that take their godforsaken time, when a user could quite possibly be nibbled to death by ducks while waiting for a system to boot back up.