Stephen slapped Irene on Real World: Seattle in a moment so iconic, you can't even meet a girl named Irene without thinking of it!
Teresa Giudice flipped a table toward Danielle Staub on Real Housewives of New Jersey and thus a reality TV star with a temper was born.
All those little passive-aggressive comments between Sammi and JWoww on Jersey Shore finally boiled over with some fists.
Hey, remember when Chelsea's baby daddy texted her on 16 and Pregnant to say he wanted to "sign off on that mistake," meaning his daughter? We wept alongside her.
Way back in the first season of Keeping Up with the Kardashians, Kim tried to fight Khloe in a little sisterly squabble. It started with a purse to the face.
Miss New York probably didn't love getting spat at on Rock of Love, but the event probably helped her score a spin-off, so draw?
It's hard to keep up with the ongoing wars bewteen Kim Zolciak and NeNe Leakes on Real Housewives of Atlanta, but Nene's early request of "Close your legs to married men" was definitely a highlight.
Toya and Mariah tried to have a calm discussion near a pool on Married to Medicine, and almost wound up brawling in said pool. Dangerous!
Sisters Kim and Kyle Richards let their lifelong rivalry explode in one very strange limo ride on Real Housewives of Beverly Hills.
Do people quote Brooke's freakout at Collie on Real World: Denver back to her in bars? Because we would totally do that.
Viewers learned in the first season of Jersey Shore why you shouldn't mess with Ronnie: He can knock a person completely unconscious with just one punch.
There's a fight every season (every episode?) on Bad Girls Club, but one of the most unbelievable was when the whole house ganged up on one chick, leading to several cast members being sent home.
There could be a whole separate list here on how many fights have started because of someone throwing a drink! That's how it went down with Evelyn and Royce on Basketball Wives.
Noted unpleasant human being Dustin Diamond threatened Sergeant Harvey during a weigh-in on Celebrity Fit Club, and it was nearly impossible to take his side.
Erica and Kimbella literally fought over who was prettier on Love & Hip Hop, and for that we tip our hats to them.
The long simmering fight between Adriana and Joanna on Real Housewives of Miami climaxed in a solid slap across the face.
Don't cross Vanilla Ice, mmkay? The 90s rapper was so mad at costar Ron Jeremy on The Surreal Life that he decided to share his feelings by destroying the show's set.
In probably the most memorable moment in America's Next Top Model history, host Tyra Banks completely lost it and screamed at one of the girls.
Amber's attack on her boyfriend Gary in front of her baby on Teen Mom led right to her later arrest.
Blonde on blonde catfight! Daisy and Heather tussled on the reunion of Rock of Love.
"I've got Donald Trump money, b*tch," NeNe dismissed Sheree in another episode of Real Housewives of Atlanta.
As previously noted, Ronnie on Jersey Shore is not someone you want to mess with. Just ask the Situation, who ran his own head into the wall to knock himself out before Ronnie could do it.
Hell hath no fury like a Bachelorette scorned. Justin learned you shouldn't lie about having a girlfriend to Ali, who was basically America's sweetheart at the time.
Yet more champagne flutes had to die in the fight between Karen and Drita on Mob Wives. Will no one think of the champagne flutes?
George and Tailor Made got into a wee bit of a scuffle on I Love New York that may have involved a little choking, maybe a little spitting. Gentlemen, keep it together.
Jenelle and her mom Babs have had plenty of fights on Teen Mom 2, but the worst argument was over her moving out. Why would you wan to leave Babs?!
Assuring that no one on reality TV could ever use the term "bullying" again seriously, Kelly and Bethenny's fight continued into high-pitched squeals on Real Housewives of New York.
"You f*cked with the wrong girl, dude!" Kristin Cavallari won our hearts in her first episode on The Hills with her fight with Audrina.
A threesome fight? How captivating! Nia fought a couple on Real World: Portland.