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

[clemonz]

Shoveled her driveway after a heavy snow; cleaned the snow off her car.

sounds creepy.

i can't think of anything, but my acts of kindness are pretty unfathomable and enigmatic

She's an old lady. Who's going to do it for her? I figure I saved her about an hour of back breaking labor. BTW, I'm a woman. I can see how it might come across as creepy if you thought I was a dude.

it does seem a little self important - generally i mean, the wish to do something without other people knowing.

but i guess she might have refused if you had asked her.