Hearing voices
It's my theory that most workplaces with at least a couple dozen employees have two individuals whose speaking voices, when heard from a distance, sound almost identical.
That's no big deal, of course. But the other part of this theory holds that your feelings about these two people are almost invariably polar opposites.
So what happens is you hear that voice in the distance and think "Hey, it's good old..." and then look up to see it is actually the other person, forcing you to "Oh, God, it's her again."