Quite a serious problem I myself have - at least I'm willing to admit to it - is that when presented with any coding task at all, I start looking for ways to op

Quite a serious problem I myself have - at least I'm willing to admit to it - is that when presented with any coding task at all, I start looking for ways to optimize it. That's lost me more than a few jobs. It's not that I can't write fizzbuzz. It's that I won't write anything at all because I'm trying to figure out a faster way to implement it than the obvious way. Here's a little exercise for you: give your candidates what you call the "fizzbuzz test", but instead of 2 and 3, use, say, 4 and 7. I bet quite a few candidates will write out the code for 2 and 3, because that's what they memorized before the interview, without understanding what the code actually does. Source code for fizzbuzz is all over the series of tubes these days, you see.