Most people know we aren't perfect. Maybe we have a tendency to be late to school or work; we lie sometimes; we might be somewhat self-absorbed.
But to admit that you really harmed someone? That requires more from us. For starters, we need to have a developed sense of self-awareness. We also have to care (at least a little) about another person’s wellbeing; and we have to be willing to take accountability.
The truth is, we've all harmed people. We reflect the world around us, even if we don't realize it. You've probably said something racist, misogynistic, or queerphobic a time or two. You might have behaved toxically in a relationship. You could have even physically harmed someone.
Violence is seen as a rarity-- an 'other'. Although unfortunately, we all feed into it to various extents (But yes, some harm is definitely more serious than other inflictions).
Where could you do better at taking accountability?
Once you've recognized an area for improvement, here are some considerations for where to go from there:
1) Is the person you've harmed afraid or unwilling to interact with you? For their sake, you might not want to approach them to apologize.
2) If the other person IS comfortable interacting, you could tell them what you've been thinking about and how you wish you had acted. Whatever you end up saying, be intentional about not trying to make them feel bad for you. That puts them in an awkward position.
3) You could even acknowledge the impact the actions had on the other person. If the other person knows they are heard, this can help them to heal.