The song isn’t bitter or angry, and it’s not about lost love. The guy is in love, but is in denial. When he keeps her picture on the wall and doesn’t want to give it back but claims it’s because it’s hiding a stain, when he says he wants to see her but it’s not because she means much to him, when he tells her not to get her hopes up when he calls her, when he says it’s just a silly phase he’s going through, he’s lying to her and to himself about his true feelings. He’s an unreliable narrator.