They set up EVERYTHING! Some things to watch for, for fun! (WARNING: SPOILERS!)
Ever wondered why on "Survivor" if there is a player who is terrified of... I don't know... red robins why: 1) they know that and mention it and 2)suddenly 10 red robins fly into camp? Because they interview the heck out of everyone and then make it happen. Everyone the players talk to, even casually, from the PAs to the makeup people, takes notes and uses them later. Mention you are afraid of ladies with dreadlocks who wear green ribbons and there will be one on your team!

'Bachelor': They film it FAST and keep the booze flowing, doing multiple takes (filmings) of them "toasting" to make sure they are all drinking... then all their inhibitions are down... and boom, crazy TV. A lot of shows keep the drinks flowing, even "Top Model" if they are over 21 or in another county, since it makes people do things they would not do otherwise.
"Housewives" you add that the ladies KNOW they have to cause drama to stay on the show and they are picked for their wild personalities. Same with "Jersey Shore" but the crew and production folks also antagonize the people off screen, telling secrets and causing trouble, picking fights...
On "Kitchen Nightmares" they often pull the head chef out during the dinner service for an "interview" to mess up the timing and get things running late!
On cooking shows they will cut the AC so things melt too quickly, on adventure shows they will create things to play to people's fears, on shows about pawn shops they will pre-screen all the folks going in to make sure they get cool stuff...
They cast most of these shows from actor's casting sites but say they have other jobs so people dont know they are actors... you know, since they are not supposed to be "acting"... hahaha, right!
And the list goes on...

Still, the people can be so fun to watch! Not knocking it, just don't be fooled that it is real!
This is why I like "Project Runway", "Chopped" and ones like that. They don't make extra drama. And I love "amazing race" for the travel, but they do manipulate that one a bit, too, by the way they cast. (And I HATE seeing people be mean to one another, cruel, or fight... not for me, thank you! So no "housewives' or "jersey shore!")
Anyway you cut it the shows can still be so much fun but reality? No. My DH and I were on a reality show during our wedding... they made up where we were from, saying we lived in FL even though we had been in NYC for 5 years, saying there were shots of us "planing our wedding at our house", though it was REALLY filmed
after our wedding and at a friend's beautiful house in FL (that we WISHED was really ours!) and all sorts of other "changes" to the real story! And, we gave them NO DRAMA so they had to make up fake drama for the wedding planner! Ha! But, we loved the crew, who we are still friends with, and got beautiful footage of our wedding, so we were happy... but the show that ended up on TV had NOTHING to do with our actual story of our wedding!

(I am afraid I can't tell you which show due to contracts, since I have mentioned 'secrets' about it here, but you can probably guess!)
Anyway, have fun watching them, they are good entertainment, but know that the producers and crew manipulate the situations like crazy to raise tensions and cause lots of drama!

Personally, I have fun looking for that, too, while I watch!
So, there is a tiny bit of the scoop and some things to look for when you watch your favorite shows!
HUGS!
Sara H