When you have done something wrong to someone, you need to apologize to them for what you did. The apology shows that you admitted your mistakes. And that is the first step for you to correct your mistakes.
When you treat someone badly, you need to apologize to them. An apology is an effective medicine to heal the trauma that you caused.
However, apologies should not be made only when you are wrong and the other person is right. In some cases, apologizing doesn’t mean admitting a mistake.
It shows that you value your relationship with them more than your ego. You say sorry not because you did something wrong, but because you cherish that person and the relationship between you two.
You are willing to yield to the other person for a good relationship. You are willing to say sorry to make the other person feel comfortable. And you should believe that what you’re doing is the right thing to do. Because it is likely that the other person will understand your sincerity and they will realize their mistake.