As Nietzsche differentiated there are two kind of good: this question focus is on the contrary of bad, not the contrary of evil.
There are quite a lot possibilities to define the common term "good". Every person and group has it own definitions. It even gets worse if it gets to concrete stuff like "what is a good question".
What are those definitions of good/bad? Where to find them? How are they built, how did they evolve? How are they reasoned?
E.g. for me, "good" is a multidimensional construct you can't calculate an absolute from. Now it depends on which "glasses" you were on if you consider it a "good" joke or an ethical offense.