The Big Bang Theory first hit our screens back in 2007 and we have been all watching it on a continuous loop since. From Leonard and Penny's on and off relationship to those genius quotes, it's now hard to imagine life without these brilliant geniuses. Here are thirteen reasons why it is one of the best shows on tv.

1. That intro song...

We dare you to sing it this fast with all the words...

2. Sheldon Cooper.

That is all. God bless Sheldon Cooper

3. Bernadette's Voice

Too cute... Except she really doesn't want kids.

4. The fact that Leonard and Penny belong together.

Like Ross and Rachel...

5. The fact that they have Blossom on the show.

Yes, Amy previously played Blossom.

6. And that Amy is every bit Sheldon's match...

Just as smart, just as funny.

7. Raj's American Accent

His American accent is terrible...

8. Mrs. Wolowitz

Every mother has shouted like this at some point in their lives, not every mother is as funny as this.

9. Howard's NASA training

We laughed until we cried...

10. Sheldon's T-Shirts

We want all of them.

11. Leonard's Secret Weapon

It's pretty good...

12. Amy's Weird Crush on Penny

Weird, and yet hilarious...

13. Sheldon's Closure