Hunting the Unicorn/Tear Jerker

Where to begin with this? With all the Cerebus Retcons and Deconstruction going on, Hunting the Unicorn was literally tailor-made for making you die a little inside.

Blaine and Kurt's dreams.
"The Midnight Carnival," where Kurt cries into Blaine's chest.
"The Magician" is where we find out just how bad Blaine feels about screwing up Kurt's life.
The ending of "The Clock" is a big one, according to readers. Doubles as subverting The Power of Love and being a Meaningful Echo.
"The Princess" takes a sledgehammer to A Man Is Always Eager and Sex Equals Love, puts a new perspective on Blaine's actions in "Sexy," and Blaine sings "Samson."

Blaine: I wish it was with you.

- It gets even worse in light of "The First Time."
Terry tried to invoke a Dance of Romance with Blaine. Unfortunately, Blaine is Oblivious to Love.
Blaine can't listen to "Touch Me" without feeling unbearable awkwardness and regret.
Blaine's counseling sessions are pretty depressing in general, what with exposing his fears and insecurities. His painful, confused epiphany in "The Harpy" is particularly bad.
The end of "Drinn," where Blaine dreams about lying in bed with his first, wondering why he doesn't feel anything.

When Blaine wakes up in a basement with Wes and David, with no memory of how he got there, who's the first person he calls for help? His neglectful, implicitly homophobic dad.
In one chapter, Blaine calls his dad for help because David and Wes are drunk. He gets Kyle instead, and the narration notes that he just sounds weary, like it's happened too many times for him to be surprised.