Slightly off topic, but I have noticed that generally Thai people don't say "please" and "thank you" even though they have words for them. This isn't because they are not polite. They have other ways to show respect like saying "krap/kaa". This causes problems when they start speaking English because they don't sound so polite. In our culture, we have to say "please" and "thank you". Thai people don't understand why I say "thank you" in Thai when the cashier gives me my change. They argue that I have just given them money and it should be the other way around. But, I tell them that I am thanking them for their service. This is not every Thai as I see some say "thank you". But then maybe not as often as me. I even say "thank you" to the bus driver when I get off the bus.
I don't know if it is universal, but telephone etiquette in the corporate setting as taught by secretarial schools (I think it is American-oriented ) is to drop the use of "Hello" and instead identify the name of the office and greet the caller --" XYZ Company, good morning/good afternoon (whatever)." (The other version is, " XYZ Company, may I help you? " ) If this is the practice encouraged in Thailand, then this is easier to get used to since "Sawatdee" sounds quite natural.