I think this whole song is about the break-up he refers to in the second half of the first verse. He starts off talking about childish illusions, then gets to the point, "How come you hang the phone up the minute I walk in?". The choruses sound personal as well, so I think he's reflecting that he always thought that he had a kind of immunity from receiving bad news that would really hurt him, but now realises he doesn't.
I think this whole song is about the break-up he refers to in the second half of the first verse. He starts off talking about childish illusions, then gets to the point, "How come you hang the phone up the minute I walk in?". The choruses sound personal as well, so I think he's reflecting that he always thought that he had a kind of immunity from receiving bad news that would really hurt him, but now realises he doesn't.