The Last Five Years/Tear Jerker

"Still Hurting", probably the ultimate breakup song. This troper heard it for the first time at a theatre festival with her best friend, who had just had a nasty breakup. It could not have described what he was going through more perfectly or more poignantly.
This troper always cries when she listens to Goodbye Until Tomorrow/I Could Never Rescue You. Even though you already know everything that has happened at this point, the juxtaposition of Cathy's excitement and Jamie's miserable resignation is just HEARTBREAKING. It doesn't help that it reminds this troper of her very first relationship.
Also, there's a line that, once the Fridge Brilliance kicks in, is almost just as heartbreaking. During the wedding song, Cathy and Jamie sing about being together "Till there's no one left / Who has ever known us apart". During the show, because of the way the two timelines work, they are only actually together onstage twice - during their wedding and at the ending of the show when their timelines finally seperate. And that reflects how they were never emotionally together in the first place... :(
This troper thinks she's probably a horrible person, but she cries during "Nobody Needs to Know". It's the regret Jamie feels, and the Dark Reprise of "I could be in love with someone like you". Damn Norbert Leo Butz and the break in his voice as he does the line "All right, everyone bleeds! All right, I get what I need!".
"See I'm Smiling" and the way Cathy tries so hard to be what Jamie wants and not rock the boat. Followed by her epic breakdown when she just unloads everything that's wrong with their relationship.
Another heart-shattering instance of (a doubled layering of) terrible, terrible Fridge Brilliance causing a Tear Jerker is more subtle, and actually took a few tearful listen-throughs before this troper required an extra tissue - in "See I'm Smiling", in the middle of her rant to Jaime, Cathy sings the following:

Cathy: "And the point is, Jamie,/that you can't spend a single day that's not about/you and you and nothing but you,/"Mahvelous" novelist, you!/Isn't he wonderful? Just twenty-eight!/The savior of writing!/You, and you, and nothing but you!/Miles and piles of you!/Pushing through windows and bursting through walls/En route to the sky!/And I..."

Then, during her penultimate song to Jamie, "I Can Do Better Than That" (which is chronologically taking place at the very beginning of their relationship, but is at the end of the show, after the previous "you and you and nothing but you"), she sings the following:

Cathy: "I want you and you and nothing but you/Miles and piles of you/Finally I'll have something worthwhile/To think about each morning/You and you and nothing but you/No substitution will do/Nothing but fresh, undiluted and pure/Top of the line and totally mine!"

She also mentions how disappointed she was that her last boyfriend left her with nothing but a "heartfelt letter". The fact that Cathy's pure, unadulterated love for Jamie has been so twisted by the end of their relationship and that she sees none of it coming is heartbreaking enough, but what's worse is that Jamie's final song, "I Could Never Rescue You", is him writing a 'heartfelt' (whether this is true is debatable) letter to inform Cathy that he is leaving her after 5 years of being together. Poor, poor Cathy. * sob*
Every single time Jamie and Cathy express how happy they are in their relationship (Hi there, Shiksa Goddess and A Part Of That!), because you know from the first fucking line in the show that it's all gonna crumble.
- I always found 'A Part of That' perfectly fine until the last bit of the song. Something about the way Sherie Rene Scott sings, "I'm a part of that, aren't I?" seems to bring up a lot of self-doubt, which is then confirmed when we realise just how emotionally distant Jamie and Cathy are from each other.
"I swear to God, I'll never understand, how you can just stand there straight and tall... and see I'm crying... and not do anything at all."