Tales of the Obnoxious Tourist

DO enunciate and speak clearly when communicating with someone who has difficulty understanding your native langue.

DON'T speak in caveman talk to someone who clearly speaks articulate English.

For example(from an actual conversation):

Local: That's a very amusing idea you have, installing beds instead of chairs in the back of my little movie theater here. But somehow I doubt the novelty of it would attract very many customers. The installation would probably cost more than the extra revenue it would generate.

Obnoxious tourist: Yes, make beds in theater, no chairs. People happy, like beds very much, you make more money!

Local: Um... No, I don't think so... Very funny... [Just leave me alone, you ignorant, condescending fool!]