Let's look at the reason etiquette exists: it is to help us live with each other and is the twin of politeness. If we don't have these twins as guides, then we don't thank people or say "your welcome" instead of "no problem." We don't write a quick note for kindnesses--including a meal at someone else's house, a gift, and so forth--that sure took a lot longer than the three minutes and a stamp to write the note. It is putting yourself in someone else's place and attempting to smooth the harshness of humans left to their own devices.
It is quickly becoming a lost art, and much depends upon it. People are less nice to deal with socially, and--if I had a choice between two equally qualified applicants for a job--guess which one I hire? Yes, the one who wrote me a thank you note.
Public schools need to teach this, parents need to teach this, mentors should teach this. More importantly, people shoud do it. We do know we are supposed to; we just choose to be too "X" to do it.
The less civil our society, the more each of us suffers.

Look at Piedmont Park and Rec Department. You pay more if you don't live in Piedmont, but they have a great selection.

I am looking for a class group, sometimes they offer this classes thru the community parks but I haven't seen any lately.