Frictionless surfaces Memes

Physics textbooks exist in a parallel universe where cart-hanging people are just normal Tuesday stuff. First they give you a frictionless surface (because God forbid we deal with reality), then casually mention "a person hanging from a massless pulley" like that's something you'd see at Walmart. Next problem: "Calculate the tension in the rope as the cart approaches the speed of light while carrying 3 penguins and your crushed dreams." And we all just accept this madness!