There are, as I see it, two broad types of reality shows. The first type casts real/common/whatever people; the second follows celebrities of various grades. As one of my rules, if a celebrity is involved, I'm absolutely uninterested in the show unless proven innocent, because the second type seems to undermine the very point of reality shows.
I understand the appeal of real reality shows that follow the adventures of commonfolk to be the vicarious projection possible; if these people I've never heard of before, whom I could see on the street and not recognize, if they can be put into extraordinary situations to win a tidy cash prize and at the same time be on national television, then dagnabbit that could be me there! Sure, the shows can reveal the contestants as jerks, but then aren't we all incommensurate dickheads too? Survivor's greatest selling point is that its audience can see itself in the show itself (and the contestants) from the comfort and safety of home.
Using celebrities, though, becomes an exercise into exploitation, either of the has-been breed or of the people unfortunately in supporting roles (The Simple Life, I'm looking at you). Of the first sort, I really can't relate to C-list folks like Erik Estrada, Melissa Rivers, John Lydon/Johnny Rotten, Stephen Baldwin, MC Hammer, Frederique Van der Wal, Ron Jeremy (yes this list is the google magnet part of TCHYBE!) in the same way I could relate to the Clowns from the last season of The Amazing Race or Sandra from the last Survivor. Celebrities, for being celebs, are all image, less than human especially when we see them on television; so watching The Surreal Life or I'm A Celebrity, Get Me Out of Here has all the appeal of watching rats running in a maze.
If you're into schadenfreude, though, there's still an unappetizing scavenger-mentality to reveling in a fallen stars lowness. Watching the husk of a former-person tripping around a house/jungle strikes me as horribly malicious since they really didn't do anything to deserve such a pathetic fate. However, watching genuine schmucks, like Jonny Fairplay and ex-Apprentice Sam get shot down, is nothing short of glorious, because they engage in genuinely awful and/or questionable behavior, and with such a build up, their ignoble ends is cathartic to viewers who love to hate them.
As for that family in The Simple Life, they seem unfairly put upon by Paris and Nicole. To extend my conceit, those two girls seem to be the predatory viewers in a reality show that preys on innocent bystanders. Even though the focus, apparently, is on the pratfalls and naughty behavior of Paris and Nicole, they nonetheless victimize the Leding family in such a smug, "rural life is so different from sophisticated urban life, but we're the focus of the show because everything, including Arkansas, revolves around us" way that even when they make some awful mistake, I don't laugh because I'm too pissed off and offended. (Nb. I really shouldn't say anything about a show whose first episode I didn't watch all of, but whatever, I'm on a roll.)