Reading all of these responses has been really interesting and enlightening, thank you for your many thoughts and comments.

It seems like most women here were never comfortable going topless in the first place - why do you think that is? (Besides the weight concerns, etc.) Why is being topless such a "man's thing?" To me it always seemed like an *efficient* and *practical* thing. How nice to not have to deal with the extra accoutrement! Especially now, I've been living a few degrees north of the equator for 3 years in an apartment without air conditioning, so it's been like clockwork: come home, fan on, shirt and bra off. Relax. (And then: Is that a knock at the door? SCRAMBLE AROUND; OMG, WHERE'S MY SHIRT??)

Once I had a couple of male couchsurfers staying in my apartment. I'll never forget the resentment I felt when, with the three of us relaxing at home, I was uncharacteristically but necessarily wearing a shirt and bra and sweating bullets while they - guests in my home! - were lying around comfortably shirtless, completely oblivious to my envy.
I just got so fed up with the double-standard. I don't understand why more women don't feel this way.