Yes, it ain't always easy in TH, you have to tiptoe the line between being polite and applying a certain amount of pressure in certain cases... Like my girlfriend - if I ask something in a nice way, she says "Yes" and it'll never happen. If I get fed up and yell at her, things work out just fine. I often said that I don't want to "play the policeman", nut haven't figured out a better way yet - after 3 years... Often the problem lies somewhere else than it appears to me, that's why it's always good to have a thai person with you, they can work things out among themselves. Sometimes the next day everything works without a hitch, even though today it was absolutely impossible... Sometimes a little money is expexted, sometimes it's insulting, sometimes the money goes to the thai that is with you... I'd say you should always be polite and relaxed, respect local customs and the problems that come with it, but if they give you the runaround it's about time to express your dismay - just don't throw the computer monitor through the window, even though you feel like it...