Paul said that he had tried to avoid offending God or men. We should too and sometimes we need to ask somebody for forgiveness, if we know we have offended them. You may need to ask your parents to forgive you or a friend to forgive you for your unkind words.

On the other hand Jesus said if you come to the altar and you know someone has something against you should leave the altar and put things right with that person before you carry on to worship. Sometimes we may even have to ask Gods forgiveness for the sins of our grandparents as well as forgiving those who have sinned against us. We need to clear our conscience before God and people.

That doesn’t mean we go and confess all our sins to our parents, wife or a person we are secretly jealous at, unless they know of our sin. We don’t tell people that you had something against them for the last 10 years, if they didn’t have a clue. That may just create un-necessary problems.
Friend, a principle to live by is: Ask forgiveness from only those people that know of your sin or wrong attitude toward them; nobody else needs to be involved, apart from Our Heavenly Father who will forgive you completely as you confess your sin to Him.