Yeah, some do. Fatigue and discouragement mostly I think. It's hard to get ahead in the US with minimum wage as it is, much less prosper. I feel bad for ambitious young people trying to get something going for themselves who weren't born rich.
Don't get me wrong; I'm not against hard work, in fact I think it's a pre-requisite for success. But I can't stress enough that it isn't enough on its' own. If you aren't smart, well-organized and good with people your hard work will get you precisely nowhere.
Because in the end of the day people who could be more hard working or commited than you won't get the job cause they aren't a certain race or gender. Everyone knows that.