If you think you have enough time, that some day you will tell the person you love how grateful you are for having them in your life, how you wish they would forgive you for all the times you were impatient and thoughtless and inattentive, the perfect time to say this may never come.
As Elisabeth Kubler-Ross said: "What I try to teach people is to live in such a way that you say those things while the other person can still hear it."