It kind of upset me at first, but after 15 years here, my attitude is 'live and let live'.
I will say that many times when you see a really head-turning, heart-stopping beauty on the street you (yes, 'you', not just 'me') have to have a long, careful second look to discover it is a transvestite. Often the only giveaway is that the clothes and makeup are perfect and ultra-feminine. Lots of guys get 'sucked in' by them here. ;-)
Look at the hands and shoulders. Those usually are dead giveaways. Also, they almost always have about 10 times more makeup on than the average Thai girl.
That's the second time I've heard that. The other guy said something to the effect that the transvestites will act more feminine than real women kind of like a white kid trying to imitate a black kid from the ghetto.
Man Hands, Adam's Apple, unusual height and/or gait.
Difficult to disguise those things under makeup and silk.