I'm sort of the favorite grandchild, but to be honest I think it's just because I was around the most, I'm pretty low maintenance , and my ISFJ mother drilled etiquette into me from a young age. I've occasionally been a favorite student, and I did use that to get some leniency on deadlines (I have a terrible habit of not doing homework). I don't know why those teachers liked me though, I never made any effort to be particularly friendly with them.
On the one occasion where I was a favorite employee, there was some minor tension between myself and others. It was mostly because I was just not naturally good at socializing with my peers and I neglected that aspect in favor of just trying to be pleasant to the managers (and customers). It was more a conservation of my somewhat limited ability to be likeable than anything sinister. I could see some people finding themselves in a similar situation and seeing the need to play that up for the sake of their own ego (because they feel they are not liked by their coworkers), possibly without realizing what they are doing. That could be what you're seeing, Protean. I'm just giving the individual you described the benefit of the doubt, because if they're anything like me they might just be acting in ignorance of the social dynamic.
However I also worked a lot harder than many of the other employees, and found that the ones I clashed with the most were the ones who had no interest in doing the job well (ie they were unpleasant and lazy). Also there was one manager there who valued some quality that a few of those employees had but that I did not, and for the life of me I still have no idea what it was...anyway I was simultaneously a favorite and a least favorite, so I kind of saw it from both sides.