Is is justifiable to take advantage of the generous and good willed in society?

I think a certain amount of greed is important. Otherwise people might not try to make progress at all in this world. People wouldn't try to get themselves better lives. They'd stay lazy bums forever. Maybe without that touch of self interest and greed we'd still be cavemen, not trying to have better lives with better things in them. Of course, goodwill and generosity are VERY important. The world is built on some of both. Giving and generous people can also receive, and receiving is not necessarily greed. For instance, who REALLY wants that wet pacifier the baby offers you? Which parent wants to keep and take every torn up piece of gluey painty mess the kindergartner will be hurt if you don't accept with glee? But this is just my opinion. That is is a delicate balance we've gotten used to, humanity.