I think the term "great room" was coined to mean "living room with a high ceiling," that is, double the height of other rooms in the house. It's not the term so much as the design that's pretentious.

I understand the objection to "potty-mouth" but on the other hand, we need a term for people who use obscenities excessively. I can't think of another good term. Any suggestions?

A lot depends on context. A person who would be shy about saying "I need to use the toilet" would probably have no trouble saying "I had the plumber put in a new toilet."

It's not only Americans who use euphemisms. I believe it was the British who invented "spend a penny." True, that's a rather quaint expression, but a lot of the terms we're discussing here are becoming quaint.