Maybe it's because of my personal experience, but to me this song is about trying to forget someone you're deeply in love with after a failed relationship.
But you find that it's extremely difficult to forget, after being so close. Everything reminds you of that person, he/she had become a vital element in your life and you get that feeling that he/she is in the air you're breathing.
You meet this person again and they find that you're upside down because you're not able to get over that person.
If you got hurt, you might hold a grudge, but all it takes is a smile to get lost again.
Maybe it's because of my personal experience, but to me this song is about trying to forget someone you're deeply in love with after a failed relationship. But you find that it's extremely difficult to forget, after being so close. Everything reminds you of that person, he/she had become a vital element in your life and you get that feeling that he/she is in the air you're breathing. You meet this person again and they find that you're upside down because you're not able to get over that person. If you got hurt, you might hold a grudge, but all it takes is a smile to get lost again.