What are the most common reason why is it hard to say sorry to someone?
because we are humans and our ego will stop you to say sorry if you are making any mistakes that is the problems here available in the mindset of your one this is the thing that we need to find the solution to teach it is not tough to ask sorry
Sometime we never need to say sorry, because not all the time, we did mistake and sometime other people hurt us, and they jealous with us, and in this wise some miss-understanding happened and no one is responsible for it.
But you are right, when we did mistake or misbehave to others and we can't say sorry, so it is our ego, and our ego not allow to say sorry.