Subtle

I've been in the US now for most of the last 15 or so years, and it took me until last week to notice this subtle difference between the US and the UK when someone pointed it out to me.  In the US, it is normal for you to push switches up (such as a light switch) to turn something on, and down to turn something off.  Whereas in the UK, it's the opposite.  Boom - mind blown.  I have no idea where this difference originates from - probably the same place that decides which side of the road to drive on.