Lindsay dated playboy Calum Best, Jessica televised everything about her relationship with Nick, and Heidi's engaged to Spencer (who's a loser with a capital "L"). What is it about love that makes everyone ignore common sense?! Yes, there are some exceptions to the rule, but relationships can be tricky -- and when you're in l-o-v-e, you're even more vulnerable to little (or not so little) slip-ups. Flip through for star examples of what to do and what not to do when it comes to love!

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