Changing the world is a colossal task, a huge burden one can put on his shoulders. Some of the most stressed people i ever meet are people who are trying to change the world.
Not only you are taking responsibility for things that you are not control which is incredibly stressful.
But also that if you are going to try to make others adapt your values and strategies of doing certain things, this means being very persistent at conveying what do you believe in which can easily turn in to abusing others. After all all vices exist under the shadow of ignorance, "bad" people are not aware of the full extent of their consequences of their actions, they always find a way to justify how what are they are doing is good.
To his own standards Hitler probably considered himself a great and kind person, he just wanted to make his own country the greatest in the world how could that be wrong. Even that involved being at war with everybody and killing millions just a small obstacle in the way of a great cause.
Changing people is hard because they have free-will, they just want to do whatever they want when they want. In order to advance your cause you either have to somehow erase their free-will with violence and lies or by trying to educate them and hope that they will voluntarily make better decisions based on the information that you are presenting to them.
Either way it is problematic you will encounter resistance if you are abusive people will rebel against you, if you try to educate people they will contradict and argue with you.
Your job is not to change others it is to help them, through helping them your give your life meaning. So simply the act of helping should be emotionally rewarding in itself, when you approach life by changing others you can be happy just when other people around you are living in according with your values which is never going to happen fully.
This is why the people that took the responsibility of changing the world are chronically unhappy, it is not necessary an altruistic act as much it is a selfish attempt to control your own anxiety by controlling others. It make sense to don't limit yourself to changing others even if that involves abusing them, because you don't want to change them because you care about their well being as much as you are trying to get some relief on your anxiety.
