Another related thing is this: when I'm being held up by the starter at a TT* I'm happy to be leaning slightly leftwards, somewhat uncomfortable when upright, and very uncomfortable when a bit over to the right. That's probably to do with the same thing, I'm used to getting going from leaning over leftwards a bit and then going upright- but not the other way around.
*and I am one crappy, nervous starter. I should give up, really. Or get a trike.