Sums it up quite nicely.
Anyways, I think mankind as a general whole simply do whatever they deem to be in their best interests, and whatever the actions they end up taking can be perceived either as inherently good or evil depending upon which perspective you look at it.
Example: People need to eat, so farmers need to grow food- and thus- raze forests to make more farmland to grow more crops.
Good: Feeding themselves, their families, and other people.
Bad: Destroying an important ecosystem, which houses hundreds of thousands of different lifeforms, which other people may depend upon to thrive.
Good intentions with detrimental effects, I suppose.
In short- we think we're good.
Whether we actually are is- as displayed by the creation of this thread- very much up to debate.