As you know I have been reading about Thai culture and I'm learning to respect it very much but my question has to do more with why certain things are the way they are. For example everywhere I read it says to never touch a Thai on the head or to pass something over the head. Now I can understand this from a practical reason because I would not want someone coming up to me and invading my personal space or passing something over me which might spill or something. But what I want to know is how did this become a cultural thing and not just a common Curtesy.