From a longer piece by Michael Bérubé that nicely sums up why I don't call myself Marxist:
Indeed, if there was one thing that [Stuart] Hall inveighed against above all others in his debates with his fellow leftists, it was economism, the favorite monocausal explanation of the left intellectual. "I think of Marxism not as a framework for scientific analysis only but also as a way of helping you sleep well at night; it offers the guarantee that, although things don't look simple at the moment, they really are simple in the end," Hall wrote in 1983. "You can't see how the economy determines, but just have faith, it does determine in the last instance! The first clause wakes you up and the second puts you to sleep."