Live for who?

Everyday I drink my tea there's always a word of wisdom (which of course is a very disputable statement. I take it back. It says something.) on it. On the one yesterday it said:

Live for each other.

Im not totally sure on that one. I understand where they're headed with that one, but still not convinced.Its sweet and all. Very noble. But it raises questions. Like who will live for me? and what happen if they dont do it as good as I would?