I think it is great when they leave feedback, and I wish more of them did it.

Having said that, I would rather be whipped in public than ask anyone for FB.

I have sold 29 items and received 16 FB so far, and of course I would like a bit more, but asking has backfired in the past for other sellers and I have chosen to learn from their misfortunes!

It's great when you get it, but you shouldn't count on it- or ask for it, IMO.