He has a horrible attitude toward the firm that let him intern, in addition to the bad attitude toward those paying him to work.
If he’s referring to clients as cuss-words, no wonder he can’t get a better job. And if he’s badmouthing the people nice enough to hire him and pay him, he’ll probably lose his retail job, too.
It sure sounds like not-very-serious farce to me. My guess is that he’s writing what he hopes will be salable entertainment. And thus, being rather diligently capitalist.