When I worked at McDonald's, I had this co-worker named Andrew. He was nice enough to me, but he HATED my boyfriend who also worked there. He was constantly putting him down, and just had a grudge against the dude. He threw off these really creepy vibes too, and I worried about the safety of the pets at the local pet store because he worked third shift there.
Turns out, after he was fired from McDonald's he and his wife moved to Ohio and ended up helping their roommate dismember his ex girlfriend's body.