how often you have this conversation: a friend asks you if you heard that Jim (or whoever) died? then you say: but i just saw him last week!
then you remember when was last time you saw him.
then you think: i wish i had known that he was going to die, so i could then tell him what i thought about him, right?
it is easy to remember when was last time you saw (or talked to) some1.

but, do you know when is last time you are seeing (or talking to) some1?

if you think about it, then wouldn't you act differently any time you see (or talk to) some1?