I have a friend with no education who has been a server and bartender. When he is able to work as a server, the money flows in. He's currently working at a Brazilian steakhouse where the standard tip for a table of 4 is $36 before counting money spent on drinks, meaning that after splitting up the tips with other servers and the backroom staff, he's still making well over $70 an hour on a slow day.
Of course, when he was between serving jobs, he was working at a doggy day care for $12 an hour.