The positive sides of being female in modern American culture:
- It's OK to be vulnerable sometimes. You don't always have to put up a facade of imperturbable strength. Nobody will question your womanhood if you say that you're afraid of something, or back down from a fight, or ask for help, or admit that you can't handle something.
- It's OK to show your emotions. Not in every circumstance - you can't break down in tears in the middle of a professional meeting - but in your personal life, you can cry in front of friends, you can vent your anger verbally, you can smile and giggle and squeal.
- It's OK to be passive. You don't have to take the initiative or fight for a leadership role in every circumstance. Nobody thinks that you're weak or unwomanly because you don't actively pursue a romantic relationship and would prefer to be pursued, or because you aren't interested in a leadership role in a group setting, or whatever.
- It's OK to stand out visually. Men (at least young men) can get away with bright colours and patterns in casual settings, but in formal or businesswear we're expected to blend in to the point of almost looking like clones. And even in our casual wear, we're largely restricted to the same 5-10 styles of shirts/pants/shorts in slightly different colours and configurations. Makeup, jewelry, etc. are similarly circumscribed. Women, however, can (and are expected to) look unique and creative. All the time.
- It's OK to like children. People aren't suspicious of a woman who takes an interest in an unrelated child. You won't get the cops called on you for talking to a stray kid in a mall, the way my dad once did (he was trying to get the kid to come with him to the security booth...but that's not what onlookers assumed).
- It's OK to be attracted to men.
- It's OK not to know stuff. You don't have to pretend to be competent at everything from auto mechanics to baseball statistics. (On a related note, it's OK to hate sports.)
- It's OK to be physically affectionate with your friends. People don't assume that your touch must necessarily be either sexual or aggressive.
These, among others, are the things many men - especially gay men - envy about women. Hell, even I envy women sometimes. I did even when I was trying to pretend to be one. I could never fully take advantage of this stuff because I'd so thoroughly internalized the idea that these things, these perfectly normal human freedoms, were not OK for me because I was a boy. Sometimes I wish I was a girl, and I'm FTM.
But these aren't the reasons trans women transition. They transition because they are women, just like I am a man. They might appreciate some of the extra degrees of emotional and creative freedom that women have, just like I might appreciate some of the extra respect and privileges that come with being seen as male - but I'm not transitioning to access male privilege, and they're not transitioning to access female emotional freedom. Heck, some of them might not even care for it at all.