[fredley]

Taught this kind of stuff in India for a while for a company providing phone support. It's not just "thank you", it's also "please" and "sorry" - both are considered rude/inappropriate outside of certain settings. There's a huge difference in etiquette that is a cause of frustration on phone calls (particularly for support). Both sides are (usually) trying to be polite, but perceive the other side as being very rude. This is one of the main reasons (of about a half a dozen) that cause support calls to go sour.