How do you know if you are a boy or a girl?
One way you could tell is put your back flat straight against a wall , put one foot directly in front of another while in the same position, mark your furthest leg's position from the wall, get a chair, not heavy, not too light, and put bend over to the wall, while the chair is in front of your toes, pick it up to your chest, now stand...If you CAN stand while the chair is touching your chest, you are a girl.
If you CAN'T stand while the chair is touching your chest, you are a guy.
it's a quote that means when you break up the girl or boy doesn't know what they have till they don't have it anymore. which means the girl doesn't know what great boy she has till she doesn't have him anymore and same for the boy except opposite the boy doesn't know the great girl he has till he doesn't have her anymore