Selfish people ! who only want the happy part of love but not the hard part of it !

This few days have been seeing people say, " if u love me, do not change me", but i was thinking, if they love u, means they care, they want the best for u ! For instance, if ur love one is into drugs, would u tell him or her to stop it ? or u love them so much and do not want them to change, let them continue to take drugs ? or if ur parents love u, they should not ask u to change ur bad habit ?