Hunting the Unicorn/Fridge

Blaine leaped to Kurt's aid after ten minutes of knowing him. Ordinarily this would be a Marty Stu trait, but it's revealed he didn't even consider the possibility that Kurt wouldn't tell the truth--if Kurt had been someone else, or even if he'd met Blaine before he stopped being a Manipulative Bastard, things could have gotten ugly. And they did.
He's gentlemanly and chaste because he slept with a guy at sixteen, thought Sex Equals Love, and ended up strung along for weeks because the guy had no intention of taking responsibility. Which means that the Warblers' constant Lampshade Hanging that Blaine is too uptight and will wait till domestic-partnership to sleep with Kurt? No longer funny.
- It's getting better with the Reconstruction taking place.
The destruction of Blaine's Relationship Sue status reaches a new level of Tear Jerker when you realize that outside of the Warblers, Kurt and Greg are the only two people who genuinely care about him and are physically there to show it.
Both in- and out-universe: if Finn's locked in Kurt's car trunk, then what happened to Kurt?

Considering how close-knit the Warblers are and how low Blaine's self-esteem is, it's not hard to think that they give Blaine a lot of solos in-canon because they think he's intentionally passing them up.
Blaine thinks Kurt is his sweet, helpless boyfriend, when he's actually a defrosted Deadpan Snarker with a side of Don't You Dare Pity Me!. Similarly, it's implied Blaine thinks that unicorns are the helpless, innocent ones of Victorian fiction, when the original unicorns were the embodiment of wilderness--meaning they are vicious creatures who cannot be tamed by ordinary means. Unicorns' Bambification parallels Kurt's constant Ukefication.