When..

When u really LOVE someone as u never feel before and u have to let him/her away cause of such reasons which should not be.

When u lose someone and will never get him/her back.

When u realize that he/she is so important in ur LIFE but u can not reach him/her anyway.

On the other hand, u let ur self fall in love with another ONE only cause of ur impatience.

Then time goes and u will live in a pretend forever.