How I Met Your Mother, Season 2

Ted:
Wha...I don't get it! Why won't Robin tell me why she hates malls?

Barney:
Ted, you should be happy Robin has a secret. The more you learn about a person, the better chance you have of hitting the fatal "Ohhh..." moment.

Marshall:
The "Ohhh..." moment?

Barney:
Yeah. That moment when you find out that one detail about a person that is going to be a deal-breaker.

[Flashback to Barney with different girls]

Girl #1:
It's a promise ring. I made a pact with God to stay a virgin till I'm married.

Barney:
Ohhhh.....

Girl #2:
I don't have an eating disorder, it's just when I put food in my mouth, I chew it and then I spit it out!

Barney:
Ohhhh.....

Girl #3:
I just turned 30.

Barney:
Ohhhhhh.....

[back to present]

Barney:
So trust me, you want to postpone knowing anything about each other for as long as possible

Ted:
Hmm...I disagree. If there's some potential "Ohhh...." moment, I wanna know about it right away. I mean, what's the alternative?

[flash to Robin and Ted at the altar]

Priest:
I now pronounce you man and wife.

Ted:
I love you.

Robin:
I used to be a dude.