Why do slow walkers swerve and drift?

[M A V I C]

pdq wrote: Edit: Also, when you slow walkers suddenly realize someone's catching up to you and you jerk your head around in alarm, should we look at you? Stare straight ahead? Pretend we're distracted by something across the street? I know - we should probably excuse ourselves in a friendly way (for what?), but that's asking a lot for some of us scandihoovians.

YES. I need to know this too!