I only added the episodes that have significant scenes for their relationship. Pick your least favorite.

This is gonna be so hard, I don't know what to pick yet, gonna answer this later. :)

or sectionals i'd say :)

Hmmm, I'm gonna vote for Hairography.
Douche!Puck at the end is the reason, plus the other episodes have brought much more to Quick:
Preggers: this one cannot go out just now, it's their first scene EVER {they had me at 'Sup, MILF?', anyone?} and we saw jealous!Puck, which I loved.
Wheels: it's quite obvious here, the entire ep was literally Quick heaven.
Hairography: ADORED all their moments and eyesex until you-know-what, so this episode gotta go. Even though they shared that meaningful look at the very end during True Colors.
Sectionals: they only had like ONE moment here, but it was significant. Yes, Quinn left him standing there like a sad puppy, but Puck saying "I WANNA BE WITH YOU. I'M GONNA DO EVERYTHING I CAN TO BE A GOOD DAD TO OUR BABY" takes the cake. This one cannot leave either.
Theatricality: Now THIS is the episode that surprised us all! After being scarred by Ryan with the inconsistency of their storyline {or should I say NO STORYLINE AT ALL?}, Puck comes in front of ALL Glee club and wants to sing to his babymama and daughter saying HE REALLY WANTS TO BE THERE WHEN SHE'S BORN. This time singing for the girl he TRULY cares about. Not cause the Good Lord wants him to get in someone's pants. Not cause he wants to regain his popularity. He sang what he felt. Also, we got hilarious!Quick. Lol, Jackie Daniels.
Journey: this is an obvious one like Wheels as well. Sex flashback? ILY? SWOTR meaningful look at the end? YEAAAAHHHHHHHHHHHH.

I had picked Sectionals,but Nat's comment changed my mind,xD.

Still going with sectionals!

Sorry Nat but I can't choose their eye-sex episode Hairography.This is the episode that I totally fall for them.I have started to love them from baking but after this episode they become my new obsession.So I'm going with preggers but it was hard.

This was hard. I was going back and forth between hariography and sectionals. I went with hairography because well I agree with Nat, that sectionals can't go just yet cause the "i want to be with you and I'm gonna do whatever it takes to be a good dad to our baby" was significant and meant so much, while in hairography puck is a jerk and all "baby, I'm dude I have needs" and you know. I loved the other Quick scenes we got in that episode though.
&& what preggers?!No way, that was the first time they had scenes-it just made glee for me :)

OKAY well i did choose, 1x04, but after reading what Nat said, this makes more sense, they had that awful fight after cause of Puck

and in 1x04, it was different, he confessed he wanted to be there for the kid! plus there first scene, a moment of QP it was awesome.
and the way he got jealous, i just thought it was adorable, cause puck being jealous? NO WAY.

I hate you Nat, picks so hard like this shouldn't be allowed here ;)

I chose this one because that Sectionals scene wasn't as tuching as the others.

Wow, Hairography is about to get voted out. I'm glad it's not Preggers!