I've worked beside a few people who stank, I don't get it either. I can only assume they've got something wrong with them and are both too lazy to wash and can't smell the stench themselves.
One guy who worked here was so bad it could make you feel sick. The women who worked near him complained about it told him to his face, gave him bars of soap, you name it. He never changed, insisted he was clean and had no idea what the problem was.
Incidentally, the same guy went on to drive busses after he left, rolled one over on the Heathrow slip and is now in jail for killing a couple of the passengers. It's a bit of a shame, he obviously has a few issues but he's a really nice guy.