@Ivon *******
you get a 30 or 60 days stays permission. You don't hold a visa. Visa you only get at thai embassies or Konsulates or at an immigration office inside Thailand. The so called visa on arrival is a permission to stay for tourism 30 to 60 days.
And what do you think? You are american and you don't need a visa like everyone else? Funny, I'll tell my neighbor, he is American.