Lyric discussion by gentlestar 

Cover art for Islands lyrics by Young the Giant

I think this could be about unrequited love.

A boy falls in love with a girl, and he really wants to be with her and get close to her but she doesn't let him in. She is an "island", all by herself; alone.

The part about "five days" could be how fast it took him to fall in love with her, and "have you missed my warmth" could be that they never got to have a relationship, and he's saying does she miss what could've been, had she let him in.

Beautiful song, by the way. One of my top three favorite off this album.

My Interpretation

This band is a piece of work. I am laughing my fat ass off over here. Do they believe the shit they sing 'cause nobody else does. It's OK, Shaggy, not everyone can be a champion. Some have to settle.