World wars fought together? Differences in foreign policy opinions? Too much selective history brought up by Wallyam Wallace and Rob Roy stories? Devolution bringing about a more Scottish identity?
I'm all for independence but have no dislike of England at all, they are after all brothers to the Scots after many wars and much bloodshed. The sporting rivalry is a friendly one and we love getting one up on our neighbour. I have many English friends and love the country having lived there for a few years (my son was born there).
Maybe this sums it up nicely...

EDIT: I got that from Facebook btw and was obviously written by an English guy.