I'm slowly developing a British accent due to watching an excessive amount of Top Gear and Doctor Who on BBC America as well as British LPer's on YouTube. I once got in trouble at school as well because I kept using 'colour' instead of 'color' in one of my papers and the teacher insisted it was a spelling mistake. She wouldn't accept it until I fixed it, and I would just tell her that it is a proper way to spell it. I had to change it eventually though :(