Penny (Kaley Cuoco) is the heart of The Big Bang Theory (everyone else is the brain). She's the Sheldon (Jim Parsons) whisperer who listens when he has feelings to express and who empathizes with him when no one else does (mostly — even she has her limits). Her relationship with him — the dumb blonde and the awkward genius are best friends — is one of the best parts of the show. Many of their greatest moments are included in this video.

But Penny's primary relationship isn't with Sheldon. It's with Leonard (Johnny Galecki), with whom she has another odd couple relationship. Their relationship, growing from neighbors to spouses, has been the show's main story, and is well represented here as well.

Penny's relationship with her girlfriends Amy (Mayim Bialik) and Bernadette (Melissa Rauch) leads to a lot of laughs, too, often at Penny's expense. But she gives it as well as she takes it, as you'll see.

The Big Bang Theory airs Thursdays at 8/7c on CBS.

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