Here are some easy ones, none of which fall foul of your complaints: 1) You do something you thought was right and then afterward, someone explains something t

Here are some easy ones, none of which fall foul of your complaints: 1) You do something you thought was right and then afterward, someone explains something that makes you realize it was wrong. 2) You happen to not be a robot, and you let emotion, thoughtlessness, carelessness, etc get the best of you temporarily, perhaps because you're distracted or tired or stressed. In a later moment of clarity, you realize that you disagree with your behavior and you make that clear to the other person. Apologies serve a pretty significant functional purpose. They're a relatively costly emotional signal to someone that you are aware that what you did was wrong and will try to avoid it going forward. Note that this is why apologies tend to be more relevant with those you have an existing relationship with: with strangers, it's both easier to fake sincerity and it'd never checked that your following behavior is consistent, so the signal is a lot less costly and thus less useful.