The Big Bang Theory has it's cast of crazy characters, but none are anywhere close to being as loony as Sheldon Cooper. I'll admit now, I am a Sheldon Cooper fan.

Nothing has ever reminded me more of Sheldon Cooper than the likes of this "Smart Cat Knocking on the Door" video above. I'll warn you now, I watched the video and laughed so hard I swear I broke a rib.

After regaining my composure from laughing so hard. I realized that if a cat could be trained, which of course we all know cats can't be trained because they're highly intelligent and independent thinkers. I'm just saying, if a cat could be trained, then Sheldon could've trained this one.

The video below is that of Sheldon Cooper doing his signature door knock. A bit of advise though, if you're looking to start a fight with your spouse or wish to get a 'legal separation' started, try the Sheldon knock. Otherwise enjoy this video knowing you have what it takes to drive people crazy.

Big Bang Theory's Sheldon Cooper Knocking