Just for the record, i dont think you lack common sense.
My comment is based off my buddy and his wife buying (or whatever you call it) a timeshare in Florida. Its a ridiculously small time they can use it....like 3 weeks or something. I never understood why this would appeal to anyone. Keep in mind, one of my buddies most famous sayings is "its only xxx$$$ per month." So, i know they used it the first 2 years they had it, and then he told me dragging his son, daughter in law and their 2 kids down to FLA was really expensive, and pretty much, not feasible to do every year. His is also "use it or lose it", which i think he has done the later more so lately. Never made sense to me to be tied to this thing, without any real ownership. Oh, and now he and his wife are divorced, so god knows how that works.