Often, those types of results refer to drivers' self-perception. The paradox is that it isn't self-contradictory, since "above average" is not defined. The old lady who drives ten miles per hour under the speed limit may consider herself "extra careful". The fellow who cuts others off at high speed may think himself better than other drivers because he has managed to not hit anybody, yet.
Aggressive, relaxed, workaholic and wonkish managers tend to paint their preferred behaviours (compulsions?) as superior, which might be why they adopted them in the first place.