I believe Erik Ries said much of the same thing in a talk I saw once (can't find it now, of course). The gist of it was that nobody likes to get angry, and angr

I believe Erik Ries said much of the same thing in a talk I saw once (can't find it now, of course). The gist of it was that nobody likes to get angry, and angry customers are therefor especially important because they actually care enough about your product to get angry at you for screwing it up.