I tried to tell him that on the contrary my parents are quite happy and enjoy life. OK, I was that Marxist professor from the other class, but, in reading this account, I see that I didn't say what I wanted to say.
Professors can be just as exploited as roofers.
This doesn't mean that people in these jobs can't be happy, but, I think both roofers and professors stand a better chance of resisting their exploitation if they understand the processes of capitalism. Hence the need for both roofers and professors to read Marxist theory. Of course, some kinds of work are more exploitative and more alienating than others, and some people have more or less opportunity to choose a kind of work that appeals to them. Thanks to Dr. Strickland for taking my questionings in a constructive way.