I do the same thing all the time- it's mostly just my way of driving... I don't accelerate to show off, or race or anything like that, I just get up to the speed limit a bit faster than everyone else. Must be that old Army training kicking in or something. I'm pretty sure, and please someone correct me if I'm wrong, but within the confines of safe driving, there is no law dictating how long you have to take to get to speed, as long as you don't commit exhibition of speed or racing.