Pam has to stay in NYC after she failed a class. Jim is awesome (isn't he always?) and tells her she should stay and take the class even though he wants her to come home so badly. She's really torn up about letting him down but she's going to stick it out. All that would give this maybe a 7 or 8 rating. Keep in mind that's an Office 7 or 8. Not a 7 or 8 compared to what's usually on TV.
And then there's the end. Just like in Casino Night, The Job, Niagara, etc. We think we've got an ending and that's when the fun starts. The episode page here at IMDb has the clip. It's one of the prettiest scenes I've ever seen of Jenna. And I'm a huge fan of hers. The lighting has everything to do with it. If you want to know why they call it the "golden hour" in film you need look no further than this scene. The sun glows off her hair and face. She's not dressed up like in Casino Night or Niagara. I'd still argue she's never looked better.
And then Dwight has to ruin it. But that's life and that's what The Office does so well. They couldn't get in the car and go home perfectly because life isn't perfect. But life isn't about being perfect. It's about having moments like the one these characters have.