Brain

I read a study once that said there something your brain does when you're walking through crowded places that stops you bumping into people by makeing tiny adjustments in the direction you're moving in. And once you notice you're doing it it all goes wrong.

My brain* was obviously not doing whatever it was supposed to tonight as I must have walked into 20 people crossing  the station.  

* I could pretend it was them but I'm pretty sure it was me.