6. Dennis Nedry - Jurassic Park
Not only is Dennis Nedry unpleasant to look at and even more unpleasant to interact with, but the guy is basically responsible for the events of Jurassic Park, shutting down the security fences while he attempts to sneak a dinosaur embryo off the island for his own gain. He might be a talented computer whizz, but his personal ethics make him a serious personal liability, in that if you're in the business of running a Dinosaur park, there's a good chance he might cause your guests to get eaten while at once cashing in on it. He might make it through the interviews on his cocksure demeanour and programming prowess, but take one look at this smug blob and tell me you'd actually want to employ him? Even if you did, too bad, he's dead now.