Johnny Galecki as Leonard Hofstader
Johnny Galecki as Leonard HofstaderFacebook/ The Big Bang Theory

Johnny Galecki, who plays Leonard Hofstadter in the popular CBS show "The Big Bang Theory", turns 40 on 30 April. Although Galecki has appeared in many movies and some TV series, it is his role in "The Big Bang Theory" that earned him the popularity he enjoys even today. In fact, he has won a Satellite Award for the role and was nominated for Teen Choice Award, a Primetime Emmy, a Golden Globe and People's Choice Award, among others.

In the show, most of Leonard's misfortunes originate from the adamant nature of his roommate Sheldon Cooper (Jim Parsons) and the unlikely romance between him and Penny (Kaley Cuoco).

Here are some of the best quotes of Leonard from all the eight seasons:

The Fuzzy Boots Corollary (Season 1 Episode 3)

Penny: Was this supposed to be a date?
Leonard: This? No. No, of course not, this was just you and me hanging out with a bunch of guys who didn't show up, because of work and a colonoscopy.
Penny: Okay, I was just checking.                                                                                                        Leonard: When I take a girl out on a date, and I do, she knows she's been dated. Capital D. Bold face, underline, like Day-ted. I think I might have a little concussion, I'm going to go lay down for a while, good night.

The Panty PiƱata Polarization (Season 2 Episode 7)

(When Penny tries to pick up an argument with Sheldon) Leonard: Penny, you don't want to get into it with Sheldon. The guy's one lab accident away from being a super villain.

The Vartebedian Conundrum (Season 2 Episode 10)

Stephanie: I don't see anything at all Sheldon.
Sheldon: Ah. Well, you're the doctor, but I am constantly hearing this annoying sound.
Leonard: Me too.
Sheldon: Is it a high frequency whistle?
Leonard: No, it's more of a relentless narcissistic drone.

The Large Hadron Collision (Season 3 Episode 15)

Leonard: We're going to Switzerland to see the CERN supercollider. And ski. We'll also go skiing.
Penny: We're going skiing in Switzerland?
Leonard: Well, you'll ski, I'll fall. But yeah, we will be in Switzerland for Valentine's Day.

The Bozeman Reaction (season 3 Episode 13)

Sheldon: What if someone kidnaps me, forces me to record my voice, and then cuts off my thumb?
Leonard: I'll send them a basket of muffins.

The Prestidigitation Approximation (Season 4 Episode 18)

Leonard: Last night, me wanting to try that stuff out of the Kama Sutra, was that fun for you or kinda racially insensitive?
Priya: Yeah, just because you're in bed with an Indian woman, you think that gives you permission to use crazy positions from an ancient Indian love manual?
Leonard: Hey, if you can find a book called Weird Sex with White Boys, I'd be okay with that.

The Date Night Variable (Season 6 Episode 1)

Leonard: I got all your favourites. Beer, wings, sliders. We can watch the football game. I even painted my stomach.
Penny: Go Sports?
Leonard: Well, in case you were in the mood for football, I didn't want to look ridiculous.

The Bakersfield Expedition (Season 6 Episode 13)

Penny: Damn, you've got more makeup than I do. You've got better makeup than I do. Yeah, I'm borrowing this.
Leonard: Hey, hey, hey. This is my Comic-Con makeup. I love you, but there are some things a man doesn't share with his girlfriend.

The Romance Resonance (Season 7 Episode 6)

Penny: Sheldon, you wanna take a break? Your food's ready.
Leonard: What are you doing? He's both happy and quite. It's like seeing a unicorn and big foot at the same time.

The Fortification Implementation (Season 8 Episode 20)

Leonard: Hang on, if you're making all this money, where is it?                                                        Penny: In a safe place.
Leonard: What does that mean, under your bed?
Penny: No, it means a diversified portfolio of stocks and bonds. I'm not overly conservative. I'm young, so my guy said I can afford to take some risks.
Leonard: Wait a minute, you have "a guy"?
Penny: Don't you have a guy?
Leonard: Why would I have a guy?! I don't have any money!