Culture plays into it too. For example here in Finland, school grades are from 4 (failed) to 10, and that ends up skewing how you see any scale from 1 to 10.
As a bit of trivia, originally there were grades lower than 4, but at some point it was decided it wasn't necessary to determine just how badly you failed. Knowing that you did should be enough. So all the failing grades were bundled up into one, which ended up being the previously highest failing grade.