A
good deed is any
action whose expected
beneficial results outweigh its
baneful ones. Sometimes it is easy to tell that an action is a
good deed; sometimes it is very
difficult -- because the results are
unknown, or because the
interpretation of the results as
good or
bad is itself disputable. Drawing the line between good deeds and
bad deeds is the study of
ethics.
Many years ago I was a Boy Scout and was taught to do a good deed daily. Whatever one may think of the BSA these days, I think this is still a useful aphorism to bear in mind.