This is a Salmagundi Special Edition: stupid things that people do.
Perhaps it's a personal failing in me, but I do tend to find these things hilarious. (Ov corse i r sew mutch smrter.)
For generic FAIL, the icanhascheezburger people have got failblog.
And while not speaking a second language well isn't particularly stupid, the results can be very funny. There is the classic Engrish, for funny English language mistakes. And the cheezburgerz now have their own variant, Engrishfunny. And for some balance, there is also Hanzismatter for funny English speaker mistakes with Chinese and Japanese - especially on tattoos.
The Darwin Awards have been around for a while. It's about people removing themselves from the gene pool in especially stupid manners. Not always in the best of taste. Oh no.
Doctors and nurses are also not known for their good taste in humour. Student Doctor Network has this jaw-dropping Things I learned from my patients thread. And allnurses has a similar discussion.
Computer people have their own classics - we probably all know the cup-holder and "too stupid to own a computer" stories. There's a good collection at Rinkworks, and for some industry reporting, the daily WTF is often good.
Retail sales like to point out that the customer is NOT always right.
I once saw a lengthy thread about professional cooking mistakes at some chef site, but I can't remember where. I found another one at JamieOliver.com, though. And I know I've mentioned cakewrecks before, but it's worth a reminder.
Got any favourites of your own?