There are mentally ill people (like psychopaths, sociopaths, and narcissists).
There are foolish people.
There are cowards.
There are people who were poorly raised.
There are naive ones who believe that everything they do is right.
No one ever does something hurtful intentionally (excluding psychopaths, sociopaths, and narcissists).
Every action that someone perceives as harm directed at them is, to the person committing it, either not considered harm at all or, at worst, seen as justified harm — an act done because they felt they had no other choice.
There are no mentally healthy individuals who simply hurt others for the sake of hurting.
If you keep this in mind, living becomes much easier.