Most, if not all, of these problems can be done away with if you don't assume that utility is linear, but e.g. logarithmic.
Then things like enjoing one cookie slightly more than somebody else isn't a problem, because enjoyment of ten cookies is not much greater than enjoyment of nine cookies and you can have a spare one for somebody else.
Then things like enjoing one cookie slightly more than somebody else isn't a problem, because enjoyment of ten cookies is not much greater than enjoyment of nine cookies and you can have a spare one for somebody else.