Well, we can take it like in following both examples/possibilities:
1) Let me slap you 5 times a day, 35 slaps each & harder every day, leaving you scars & injuries ... for one month!! Eventually as it might be very lucrative, I sell your person/body to some gov. entity to make genetic experiments on you in order to find out how it looks like to be a genetically altered human being ... all this for "the greater good" ..of course .. :-)!
2) Now, let's do exactly the same but instead of slapping you all day long,
I help you 5 times a day with whatever comes along, make you breakfast, diner, care about if you like it or not, want to know and interested in what you do, how you feel doing it, prevent you to do mistakes when I see that you might do some very soon.
Even accept to disagree with you but can accept your choices .... for one month!!
So, someone who can't tell the difference after these 2 Month ... must have serious neurological issues.
But I guess we know when someone is evil or good to us, except we've been seriously Brainwashed ....
Observe healthy normal children & you notice a healthy understanding with no false compromise whatsoever about what good & evil is for them ;-)!
There might be gray areas all along the way, but even here, we should honestly recognize when we have the right to do something towards others or leave it, based on respecting the choices they make. One leads to freedom, the other to fascist behavior, no matter who you're dealing with because you've the pretention to believe knowing better for others what's good for them (remember the slaps here... ;-) ...)!
But I guess that, treating others like you want to be treated should be a very good way to go!!!
Now what do you prefer?