Oblivious to Love/Fan Works

Examples of in  include:

"Sam coming too. Good thing, as will enable me to have more of those platonic, brotherly foot massages he's so good at."
 * Turned Up to Eleven in Kyon: Big Damn Hero, with Kyon completely unaware of the affections of  He's also incapable of spotting the polyamorous relationship that several other characters share. Even Mikuru worked that one out.
 * Frodo in The Very Secret Diaries is oblivious to the fact that every single member of the Fellowship wants in his pants, and tries to flee to Mordor when he figures it out.

"Twilight: Dash, has anypony ever had a crush on you? Dash: I don't know. Maybe? Twilight: Well, one does now... Dash: Who is it? Twilight: [ Face Palm ]"
 * Take any franchise where there are multiple love interests bet that there will be at least one character who is oblivious to the affections of another notable character. This is also applicable to original author made characters as well but this is harder to develop so it is rarely done well.
 * In Hunting the Unicorn, Blaine's trust in people and his inability to gauge when people are interested combines this into Fridge Horror: If Blaine didn't get the picture when Kurt was all but throwing himself at him, nor when his old high school friend tried to invoke a Dance of Romance, it's only logical that he has no clue when  .
 * Rainbow Dash in the My Little Pony: Friendship Is Magic Shipping fanfic "In the Rain". Twilight Sparkle's "hints" grow progressively more elephantine, from rhapsodising about storms using terms that also apply to Dash, to straight-out telling her about lesbianism and how it's not too uncommon in Canterlot. In the ending with the Relationship Upgrade, we get this gem:

"Kissing Lily was being touched with purpose but even that was sort of a joke, and now he's thinking about kissing, and is that why Sirius has licked his lips twelve times in the past thirty seconds? "Oh," Remus says suddenly. "I get it. I'm rocks.""
 * Twilight is more often on the receiving end of this trope; for instance, in the fic "Twilight Learns a Secret", she got several months into her relationship with Dash before she even realised she was in one. And that was only because RD kissed her, and then spent several pages explaining the situation. Possibly with diagrams.
 * In The Shoebox project Sirius believes that Remus is oblivious to love.