This thought is days old, jotted into email the night of the Decemberists' concert but a day or so old even then. Copied out of email:
Generosity is like a social acid test: extend a bit of yourself, expect nothing in return, but see what comes back. Try to make sense of it, try it on for size, see how much you like it. See how much you
can count on it. Extend a bit of yourself and see what it gets you.
There is some danger there, though, because "see what it gets you" can be confused with "see what it's worth" and the two aren't really alike at all.