You will see such marvels as a scrap piece of plywood, with screws in it, and twine entitled “Constructing the Letter “H”.
My rule of thumb is, "If it's something even I could make, it ain't art." Since I can at least draw stick figures, I'd say that puts me one up on "modern artists".
How hard is it to place a crucifix into a jar of urine? Most people would never do that but an artist would.
One time my wife had a college assignment to visit an art museum. One room was dominated by 4 giant styrofoam boards 20 feet by 3 feet by 3 feet, arranged in a large square. As we were reviewing the museum guide a security guard came over and asked us not to sit on the artwork. Somebody got paid for arranging 4 huge pieces of styrofoam and calling it “sandwich”.