If you're doing something unethical.

For instance, if you were sitting around a table of your peers, and everyone was sharing their steem experiences about what great stories they wrote, which ones got paid well, which ones didn't.

...and if you stood up, and say "well, I found a way to cheat the system." and explained how you do it...

If one of those people started grinning and said "oh, you're so bad, it never even crossed my mind to do something so evil like that to scam even more rewards than just contributing content or witnessing blocks"...

...then that would be evil.

Even better: If what you are doing is a secret. You don't want anyone to know what you are doing, or how you do it. Generally that could be considered evil in some way.

If it's so taboo that you don't want anyone to know about it, or broadcast how you do it, because you have an unfair advantage that would be negatively looked upon you if everyone knew.. that's evil.

Give us the exact definition of being evil here please, so that we can understand what that means and so that we can avoid such actions.

If it feels wrong... if it feels like you found a way to exploit the system for which it was not intended... then that's evil.