Ben Finney responds to me with, "I don't see how 'for enjoyment' is
usefully separated from 'to serve their own selfish needs'."
An example of the latter:
A man is starting to get hungry, and sees a bakery. The baker's
assistant is watching the shop and selling bread. The man beats the
assistant to a pulp so she cannot interfere, then takes the bread and
eats it to assuage his hunger.
An example of the former:
A man is starting to get hungry, and sees a bakery. The baker's
assistant is watching the shop and selling bread. The man beats the
assistant to a pulp because he enjoys her pain, but leaves the bread
alone because he's in the mood for cheese.
Warren J. Dew