At first blush, it seems like a no brainer; everyone knows, or remembers, the electric jolt that comes when we cross what I term the "drag meridiam". That's the first moment in the transformation process when there is an unfinished woman looking back at you in the mirror, and not simply an oddly attired and toileted male.
We have all experienced the flash of hormonal heat that happens when you are out somewhere and you hear, "Miss", or "Ma'am" or even "Hey Lady". And there are very few things a person can do with their clothes on that supply the emotional rush of glimpsing yourself in a window or a mirror and seeing the woman who lives inside you walking and talking and interacting with the world.