I've never asked anyone fizzbuzz, but I have seen people badly flub very easy algorithm questions that are basically at the same level.
In every case it was because they over-complicated things. They came up with elaborate logic that they didn't need and then got lost and didn't quite get to a working implementation. Picture, say, starting to implement fizzbuzz using two tries and an associative array.
I would guess that a lot of the people I've seen bomb these kind of interview questions are actually good, capable programmers, but they just got overwhelmed by interview nerves and got lost.
In every case it was because they over-complicated things. They came up with elaborate logic that they didn't need and then got lost and didn't quite get to a working implementation. Picture, say, starting to implement fizzbuzz using two tries and an associative array.
I would guess that a lot of the people I've seen bomb these kind of interview questions are actually good, capable programmers, but they just got overwhelmed by interview nerves and got lost.