The first time I ever had anyone balk at my cash was 20 years ago when I tried to buy a car and the guy told me he needed a check. It has gotten so much worse since then that now I only keep $20 or so in my wallet any more.
The annoying this is that it's hard to spend $50 bills even though they're worth 20 1989 dollars when nobody would treat you like a suspect then for spending them.
Weird. I bought a used car in Canada last week, and paid about two thirds by check, and the rest in cash, with a bit also on a credit card, just to collect points. Cash is still good in Canada, at least for the moment. It remains popular because the TAXES ARE TOO DAMN HIGH. There, I said it.