I worked at our local amusement park this summer part time (I have a regular good paying full time job) and I can understand how you could easily get disgruntled.
People gripping about their kids being to short was a big problem, and there is not much you can do, except say your sorry. People mad at you about the waits for rides, People upset at you when the ride goes down for mechanical reasons and you can't explain how long its going to be, people mad because the ride is down for weather.
That's just the normal every day stuff. Then there is the fact that you only get paid $7 an hour, and some of those kids have to work 60 hours a week. They work really hard, for lousy pay and even lousier hours, doing the lousiest work ever. Think about it cleaning up cigarette butts, pulling trash liners full of pink melted slushy, cleaning up "protein spills", and working in 105 degree heat, lots of fun.
It is fun though, and I found it to be very satisfying, in the end it just boils down to how you look at it. If you go in and want to have fun, you usually will, if you go in thinking oh this is going to be aweful, then it will be.
Jennifer