The word "wonderwall" means "the person wewe constantly find yourself thinking about". This song is simply about the feelings human beings get when they experience the initial stages of upendo and infatuation (limerence). It describes the volleying between euphoria and agony that a crush can make wewe feel.

In other words, the song "Wonderwall" is basically about the butterflies wewe get in your stomach when your crush walks into the room and the thoughts that stem from those feelings.

"Today is gonna be the day
That they're gonna throw it back to you"
> He's saying today is your opportunity to express...