The only thing I have trouble with these days is neckties. My current employer is a very casual office where everybody wears jeans, so when I go for job interviews (looking for something that pays significantly more than diddly), I always remember to consult the print-out from a website about how to tie the knot in a necktie, half-Windsor for simplicity. I've probably got it figured out, but in the past, that was god damn embarrassing.
Back in college, I was washing dishes at a fast-food job I had one summer, and put the plastic apron on all weird.
