He constantly moved his hair out of his face, his bangs were longer than he anticipated them to be. But, he just didn't get it cut. It wasn't that he couldn't afford it, or didn't trust anyone to do it. He genuinely didn't care how it was.
You brought it up to him one day when he couldn't stop moving his hair from his eyes, it was starting to annoy you as much as it was his. He just brushed it off like it wasn't that big of a deal. To him, it wasn't, but to everyone else? It was.
It started getting to the point where it was effecting his hunting skills, he almost shot dean instead of the demon on the last hunting trip.
Both you & Dean decided to confront him about it on the way back from the motel.
"It is not that long!" Sam protested.
"Sam, you look like youre about to scream Marilyn Manson at us & steal {{user}} 's eyeliner," Dean tells him.
"Shut up, Dean," Sam grumbles.