Why love makes you crazy: falling for a guy can cause you to act cuckoo. Here, the reasons why--and how not to go too off the wall.(LOVE AND LUST)

* Sure, falling head over heels makes you feel deliciously happy. But passion-induced euphoria can cause you to actually lose your mind (thank Tom and Katie for hitting that point home!). "When in love, your body produces mood-altering chemicals that can override the part of your brain that governs rational thought," explains Helen Fisher, PhD, anthropologist at Rutgers University and author of Why We Love: The Nature and Chemistry of Romantic Love.

While that giddiness can be pure bliss, there's a darker side to going gaga. Listen as Cosmo explains the good, the bad, and the slightly ugly aspects of romance ... plus, sanity-saving tips.

The Good

Your new man calls to say he can't wait to see you again, and everything in the world becomes a little bit brighter: Your annoying boss is a lovable curmudgeon; your claustrophobia-inducing apartment, charmingly cozy. Hell, you could be stranded in Antarctica without a coat, so long as he's around to snuggle with.

"When you fall for someone, the part of your brain that's rich in the stimulant dopamine is activated, causing you to feel exhilarated," Fisher says. And the intensity of that joy spills out into the rest of your life, mitigating any negative things that may be going on.

Dopamine also cranks up production of testosterone, the hormone that rules libido, which can explain your no-holds-barred horniness and Wonder Womanlike sexual stamina. You're probably also producing more norepinephrine, a neurotransmitter that further stimulates your sex drive and is also associated with increased memory. That's why you suddenly have the ability to recall the tiniest details about your man--even what color shirt he wore to dinner two weeks ago. "Your brain is ensuring that you cherish every moment the two of you spend together," Fisher explains.

The Bad