But you are talking the same generation, biggest concept I'm noting, is a human personality. I'm not looking at the lifetime that things were effected in, I'm looking at the proceding generation. 2 kids born to the same parents, are entirely different people, completely different likes, personalities, etc...

I agree if I mess with your individual life... most things aren't going to change a whole lot. but assuming you have kids, that's a whole new roll.

Lets look at it this way, if I randomly portalled into a minecraft server, threw a few creepers, maybe killed a guy and took his stuff, the world would roughly build more or less the same... few people would even know the difference.

But lets say those players, then create their own games afterwards. Minecraft generates the seed based on the milliseconds the clock was at. Which means if my actions, even slightly caused any player to leave that world early or stay a little bit longer, the seed of the next games they play... would be ENTIRELY different, which will entirely change how everything else comes together.

So in short, yes in the generation you effected, no one would see the difference most likely. but everyone you interacted with will have completely different children, Those children will effect even more people, also completely changing whatever children those people will have etc...