Let's Try Together
Neville is the screw-up, the joke of the school.
Harry is Harry Potter, The Boy Who Lived, and he is the joke of the world.
They see each other as much as jokes generally do. Passing in the hall, on the same side of the room in classes, in the infirmary when they happen to pull some stupid mistake with similar timing, Harry's generally intentional and Neville's generally not.
When Harry is teaching DA and right behind Neville, telling him not only everything he's doing wrong but also everything he's doing right.
When Neville feels almost physical pain over Harry's mistakes in Herbology and can't stop himself from going over to help because Merlin, that is simply not the correct way to repot anything, plant or otherwise.
When Harry is in the air at a Quidditch game and Neville thinks that it would be awfully nice to be up there with him.
When Harry isn't in the air at a Quidditch game, and Neville still thinks it would be awfully nice to be there with him anyway, but the seats next to him are almost always full.
When Harry is dead in Hagrid's arms and Voldemort has won, and Neville can't remember what he does wrong or what he does right, so much as he can remember one blindingly white smile that he always wished would be aimed at him more often.
And then he isn't, and he hasn't, and years later at a wedding, Neville sees that smile again. Aimed at someone else, yes.
But it's there, and Neville doesn't really mind Harry smiling for someone else. He's got a beautiful blond Ravenclaw as his plus one, and he's moving on.
He's just glad that they're not jokes anymore, but epics instead.