system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do some (usually low paying) jobs not accept you because you're overqualified? Why can't I make burgers if I have a PhD?
gpt
Usually because the employer is worried that applicants who are overqualified will high-tail it out of there as soon as they can find any better job. 

Edit: This can work both ways, especially in a poor economy. In the last few years, a lot of jobs that shouldn't require a college degree have been demanding them, just because the employer knows the person will probably be stuck there a while, and they'll benefit from having an (arguably) smarter employee real cheap.