Of all of the lovable characters on That '70s Show, Michael Kelso always left a mark. He's the dumb comic relief who always delivers hilariously stupid lines to break the tension. From falling off the water tower to screaming "BURN!" whenever there's an insult, you can count on him for a belly full of laughs.

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While he is hilarious, Kelso is not known for his brains. He gets by on his looks and uses them to constantly pick up girls. In fact, he spends most of his time trying to get girls, whether it's his longtime on-and-off girlfriend Jackie, one of the many women he cheats on her with, or Eric's sister Laurie. Among many others. He's clearly proven that his moral ethics aren't up to par, and you can tell with some of his signature inappropriate pickup lines. Here are some of his worst lines from over the years.

"IT'S STILL AN ACCIDENT!"

That 70s Show Kelso and Donna

Kelso constantly finds excuses to touch Donna's rear, and his pickup lines for doing so aren't always smooth. In "Red Sees Red," Donna snuck into Eric's room and runs to hide in Laurie's room, where Kelso is making out with her. Red knocks on the door and Kelso and Donna hide under the bed.

When Red and Kitty leave, Donna exclaims, "Kelso, get your hand off my ass!" He replies "It was an accident." After a moment, Donna reveals, "It's still there!" Kelso's next line is, "It's still an accident!" Eventually, when Donna points out that it's still there, Kelso just agrees.  Turns out it was no accident after all.

"I'M LIKE KETCHUP. I GO GOOD ON EVERYTHING."

That 70s Show Kelso and Angie

In season seven, we meet Hyde's half-sister, Angie. She's cool, but not cool enough to be immune to Kelso's charms. When he appears at the record store one day to try to get her to go out with him, she tells him he's not her type.

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Kelso is offended because he thinks that he's everyone's type. So, he uses this line. For the record, one of the main reasons that this is inappropriate is that ketchup does NOT go good on everything.

"GREAT, LET'S GET NAKED... FRIENDLY NAKED!"

That 70s Show Kelso and Jackie looking at each other

Kelso's end goal is always the same: get girls naked, probably for the exact reason you're thinking of. After Jackie and Hyde break up, Kelso is trying to comfort Jackie as a friend. Problem is, he's still in love with her and he hopes to go beyond just being pals.

While in Jackie's room, and she tells him she just wants to see where things go. As friends. Kelso says, "Great, let's get naked..." and when he sees that Jackie is mad, he quickly adds, "Friendly naked!"

"JACKIE, I'M SORRY YOU HAVE TO SEE ME IN THIS T-SHIRT. I KNOW HOW IT EMPHASIZES MY HUNKALICIOUS BOD."

That 70s Show Kelso and Jackie at the HUb

After Jackie accidentally yells at Annette to "get off her boyfriend" even though she's dating Hyde, Kelso is ecstatic because he thinks that Jackie still wants him back. In fact, he's loving every second of it. When Jackie shows up at the Hub to apologize later, he delivers this poorly timed line.

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The most inappropriate part is that he says this to Jackie in front of Annette, his girlfriend. Granted, he's really only dating Annette to make Jackie jealous so he just really doesn't care.

"HEY, LAURIE. LONG TIME, NO DOIN' IT."

Kelso and Laurie speak in the lounge in That '70s Show

To say that Kelso and Laurie have some history would be putting things lightly. Sometimes it feels like she's using him, and sometimes it feels like she genuinely likes him. Of course, we know how Kelso feels about her.

Laurie is known for constantly disappearing for unknown periods of time and then coming back later when she's out of money or boyfriends. Unfortunately, Kelso's classic play on the "long time, no see" line doesn't work during one of her returns.

"COME ON, HE'S IN AFRICA."

That 70s Show Kelso

Kelso says this to Donna when he grabs her ass for what we can only assume to be the hundredth time. At this time, Eric has already left for Africa, but he and Donna are still together. Donna quickly reminds Kelso that she's going out with Eric, despite the long distance.

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So in all his wisdom, Kelso says this line as an excuse to get her to let him keep touching her. As if it's okay to grab your best friend's girlfriend's ass while he's in another country.

"I HAVE THE THREE THINGS THAT WOMEN WANT: I'M HOT AND I'M SMART."

That 70s Show Michael Kelso hot

In Kelso's mind, no one should ever pick another guy over him. As far as he's concerned, all that matters in life are his good looks and hotness. When he says this line, Donna points out that those are only two things.

Kelso corrects her by saying "Nuh-uh. Hot counts twice." This line really shows his selfishness and vanity, especially his belief  that hot people like himself should automatically be better than everyone else. Additionally, it shows how bad he is at basic math.

"I DON'T WANT ANY PUNCH. I'VE GOTTA GET A GIFT FOR JACKIE... WHO I'M BREAKING UP WITH..."

That 70s Show Michael Kelso and Laurie Christmas

During the first Christmas episode, the guys are in the basement setting up. Laurie comes down with a bowl of spiked punch and Kelso leaps over the couch, crashing into the table just to talk to her.

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When he gets up and brushes himself off, he gets super awkward and can't find the right line. Later, he realizes he has to get Jackie, who he's dating, a present. Laurie offers him some punch, and he says this line. As if justifying that he's going to break up with his girlfriend is an acceptable way to hit on someone else.

"WELL, IT LOOKS LIKE I'M GONNA HAVE TO BE NUDE IN FRONT OF YOU GUYS, AND THAT'S KIND OF AWKWARD. SO, I THINK YOU LADIES SHOULD NUDE UP."

That 70s Show Kelso in Hot Tub

In season six, Kelso is soaking in Bob's hot tub while Jackie and Donna are trying to get Bob to break up with Jackie's mom, Pam. When he asks Hyde to pass him his clothes, they realize he's naked in there.

Naturally, Hyde takes off with his clothes. When he's left with Jackie and Donna, he says this line to them. In his defense, this does work in his favor because Donna and Jackie leave and he can safely exit the hot tub.

"HI, I'D LIKE AN ORDER OF BOOKS, PLEASE." "COULD YOU BE MORE SPECIFIC?" "COULD YOU BE MORE BEAUTIFUL?"

That 70s Show Kelso and Brooke

When Kelso gets Brooke pregnant after they hook up at a Molly Hatchet concert, she wants nothing to do with him. He figures out that she works at the library and shows up while she's working. Now, there's a reason that she doesn't want him to know where she works.

So, showing up uninvited and hitting on her with the above line isn't the best approach. After this exchange happens, Brooke's response is, "Could you be more lame?" To that, Kelso says, "Yes." At least he answered honestly.

NEXT: That '70s Show: The 10 Best Hyde Quotes