Conceptual artists, which create art that requires an esoteric explanation to understand the piece. What real benefit to people in society receive from some post-modern expression sitting in a museum. The art is not accessible to masses, unless you have a page description explaining what the hell it is suppose to mean. I feel like art is great, but these conceptual art posers suck resources, and are mostly in it for self-aggrandizement.
Oh, and politicians. We can definitely do without them. Their function is to serve society, but it is really about self-service.
Lawyers are necessary because they help with conflict resolution, effectuating transactions, and vindicating rights. (not all the time, but that is their supposed function).