LOL I've held most of these jobs at Disney.
Parking: it works when people listen, but because people want to park whenever they want, you lose control over the line and then people then start doing whatever they want. I know, no one wants to go "all the way to the end" (myself included), but it's the way to park thousands of cars SAFELY and efficiently. When trams were running, it was always fun being on those, gets you a break from the lot
Guest Relations: I've been flicked off, called incompetent, called an Ahole, all for doing my job. Somedays I'd have such an awful day I'd have to wait til my break, tell my manager that I have to leave, and do it. Then go home and question my life choices. Other days I have wonderful perfect guests who are just happy to be with their families and I'd love the day.
EDIT: Luckily there's a program Disney wrote for us to write notes about any guests we want, and anyone can with an ipad can pull up that information about you. That time you ripped a front desk Cast Memeber a new one 7 years ago? Oh yeah, that note is there. Probably is along the lines of "proceed with caution"