Good point, Darrin. For ages I assumed that masculine behaviour was something that "real" transmen did naturally, without needing to learn -- not necessarily due to T, mind you, but because it seemed like picking up masculine mannerisms should come naturally to someone male. If you feel like a guy, you should learn like a guy, right? But since I learned how to behave in a very feminine manner, I felt like that was proof I wasn't a "true" transman.
But with practice, that stuff is coming along easily enough. Presenting in a masculine manner helps a lot, too -- for example, now that my hair is short, I automatically interact with it by scrubbing it roughly with my palm, instead of delicately twirling a strand between my fingers.