If you believe that the origin of Christmas is the day Christ was born regardless of the dating accuracy of our calendar. The Almighty Supreme Being gave His only begotten son Jesus Christ to us for the forgiveness of our sins.
Christmas is a holiday because it is a holy day of forgiving one another of our trespasses. Gift giving is our inner sentiment and true feeling towards our neighbors and loved ones. We share gifts because we love them, no ill feeling in our heart, forgiving them without reservation.
We set aside political and religious differences to celebrate Christmas. Republican and Democrats, Muslims and Christians are forgiving one another for the sake of peace and goodwill among all people. Or we may have our last Christmas because of a nuclear war. Human hatred escalates everyday to the point of insanity and irrationality.
If the Lord God can forgive us, so we can do also. It is easier to forgive than not to forgive. Humble yourself before Him and allow His spirit of forgiveness to rule or take control of your life. Jesus taught His disciples to ask forgiveness as we forgive our debtors.
Christmas is merry because I am forgiven and you are forgiven too to start a new day. The heavy load of pride and arrogance is lifted from us. Christmas is more than gift giving. It is a time of reconciliation and loving one another.