What is the nicest thing you've ever done for someone without their knowledge?

[ChristopherSea]

I have developed life saving medicine for them.

I would think this is the opposite case - you are not actually doing anything nice for any person and you are doing it with full credit. Paid even.

Exactly the point that I was making milo. This thread stirs up the ancient philosphical debate over whether or not there is such a thing as a selfless act.