Chores are not fun but when you're the parent of a teen you've had years of practice doing tasks that are a responsibility and are not fun from changing diapers to paying bills and all the responsibilities of parenthood. You've accepted "doing for your family" but the teen is still in the mode of "being done for". I agree that when you include them in helping out as toddlers and continue it throughout childhood it becomes a habit and part of the household routine and less of a "why do I have to do this?"
Robot's point of view is valid in that teens feel like they have a full plate. As you get older the plate stays full. The "stuff" on the plate just changes.