Kristin Cavallari's Sassiest MTV Moments

To celebrate the 'Laguna Beach' and 'Hills' starlet's birthday, we're reviewing all the times she really was the HBIC.

More than a decade ago, viewers first became acquainted with the always-bold Kristin Cavallari on "Laguna Beach." The high school junior's no-holds-barred attitude, complete with her HBIC status, made her an endlessly entertaining fixture on the former hit series. She was even part of one of the most memorable love triangles in TV history -- comprised of her BF Stephen Colletti and his gal pal Lauren Conrad -- and the eye roll below truly shows what the black choker-lover thought about being a part of the well-known threesome:

From there, a senior K-Cav ruled the hallways on the second season of "Laguna Beach"; several years later, she made her triumphant MTV comeback -- and took her former arch rival's place -- on "The Hills." Unsurprisingly, the twentysomething fit right in, stirring the pot with her vivacious personality and blunt 'tude.

In honor of Mrs. Cutler's birthday -- she turns the big 2-7 today -- we're taking a fond look back at some her sassiest and sauciest MTV moments. Tell us your favorites in the comments, and be sure to offer the mother of two your well wishes for her special day!

  1. Unhappy at the Black and White party

    Perhaps K-Cav felt a bit uncomfortable because she was the only gal wearing the angelic hue, but she was NOT feeling the LC-hosted glitzy hotel affair -- and she made it no secret that she wanted to get out of Dodge pronto.

  2. The beloved white minivan hits the hay

    Actually, it was "dunzo" -- and the pigtailed teen was pretty pissed about it.

  3. Living it up, Cabo-style

    K-Cav was doing K-Cav -- dancing on bar tops and making out with a guy that wasn't Stephen -- and that didn't sit too well with...Stephen. We'll never get the image of her flirty moves with her fling Sam out of our minds -- and of course, Steeevennn yelling at her to get off the bar...

  4. A very awkward Merry Christmas to you too

    What happens when LC and Stephen are back in their picturesque hometown during the holiday season? The high school senior calls it like she sees it -- even if she doesn't have such nice words about her ex and his crush --- at a house party thrown by Lo Bosworth.

  5. The bitch is back

    Here comes the bride Kristin Cavallari, all dressed in white blue. The SoCal lady made a belated entrance at Speidi's nuptials -- in her first "Hills" appearance -- and her unexpected presence understandably got everyone talking. Especially when she plopped herself right next to bad boy, and Audrina Patridge's on-again off-again beau, Justin Bobby.

  6. It's ON

    Right out of the gate, the spitfire made sure to make her presence known among the tight-knit Tinseltown crew (did you expect anything less from the erstwhile queen bee?). Translation: digging into Audrina and Stephanie over the notorious Justin Bobby.

  7. A totally expected, but unexpected, smooch

    Understandably, KC and JB's makeout sesh didn't sit well with Drina -- who looked on at her ex and with total disappointment during the group night out.

  8. Ruffling some feathers

    With her romance with the Johnny Depp-lookalike in the past, the notorious maneater cozied up to her former boyfriend, the one and only Brody Jenner. Natch, when his recent ex Jayde ran into the duo at one of the hottest clubs in town, a fighting match ensued between the blond and the brunette -- complete with a bunch of expletives.

  9. Goodbye, Brody -- hello, Europe!

    We fondly bid farewell to K-Cav back in 2010 when the then-party girl jetted out of the City of Angels for a much-needed overseas respite. After an emotional goodbye with the notorious ladies man -- in front of the infamous Hollywood sign -- the cameras receded into what we finally realized was a staged set. What the?!