I still don't think Gaz is a bad person. He was in a bad place, but having felt like I was there myself, I can say of assurity that he was acting like most people would in that situation. Unlike the bridgemen he didn't have a Kaladin. The only people he had were his supervisor's, who constantly threatened to make him a bridgeman. Unlike the bridgemen he hadn't hit rock bottom. So he was holding on in sheer desperation, praying he wouldn't fall, while his hand was slowly slipping. If you remember a lot of Bridge four treated Kaladin just as badly at first, the only difference is Kaladin worked hard to win them over.