When someone apologizes to you, you may welcome it and be ready to forgive whatever happened and move on. Or you might not feel like being friendly again right away. If a person keeps hurting you and apologizing without making an effort to change, you might not want to hang out with that person anymore.
Just because someone apologizes doesn't mean you have to be friends. It's polite to accept and acknowledge an apology, but anything more is up to you!