Some of them have dicks.
There is something deeply wrong with a culture that thinks trannies are normal.
That's one of the reasons I always avoid a vacation in Thailand. I don't like to see trannies everywhere especially when I am trying to empty my head. I don't hate them I just don't wanna to see them I guess I have that right don't I. I mean I can look somewhere else right? And if they are everywhere then its my right to not go there.
I never understood what is so fun about about Thailand neither. Maybe because it is cheap as fuck to have sex with little kids. Disgusting.
I've been to Thailand 2x times, been there with or without a girlfriend, never really cared about the sex industry (yes, I have experienced it whilst single in my first couple of trips, but it's more like, meh). If you want a prostitute, go to Germany or Amsterdam. The trannies thing is overrated, there are many, yes, but most of them stay in the sex tourism areas, where I normally keep out of, I do go there sometimes for shock-tourism, when a friend visits me with family for example and they haven't seen much of the world. If you keep away from the sex tourism areas (Pattaya; some areas in Bangkok; Patong, Kata, Kamala in Phuket) you will have no trouble. There are some girlybars elsewhere too obviously but nothing stands out and won't disturb you.
I normally go there to let some steam out and by that I mean riding a motorcycle. Thailand (by my opinion) is one of the best places in the world to do so. You have good roads and as much as I don't want to admit this, you can speed as much as you want, never seen or heard anyone getting a speeding ticket over there. I know it's dangerous and wrong but what can you do, I guess I'm an adrenaline junkie. You can rent really good bikes for cheap and drive them around the country. And if you have any trouble with the police a fairly small amount of THB will help you out.
The nature is unbelievably beautiful at some spots and the cuisine was already mentioned here, really diverse and there's something for everyone (I guess). And Thai people are generally good, again, this applies to places away from tourist spots, I've never been ripped of or scammed over there, which has happened more than once in Europe (by Europeans).