Births occur on every day.
Marriages are solemnised on a chosen day.
Deaths are somewhat seasonal.
For the people in my family tree file whose actual dates I have on record, there are no births on 25 December in any year, and no deaths, but four marriages. Christmas is celebrated to remember the birth of of Jesus Christ, whom Christians believe is the Son of God. Apparently, weddings on Christmas Day were not uncommon in the past - it seems the date was a practical choice. During the 18th and 19th centuries Christmas Day and the following day, called Boxing Day, were often the only days of the year that a young working class couple were sure to get time off work. (Although in Scotland Christmas Day was not a public holiday until 1958). In the 1800s, most people worked six days a week and would not get paid when they did not work.
See "Here's Why There Used to be So Many Christmas Day Weddings", a Findmypast blog article.
Happy Anniversary, if it applies to you.
Merry Christmas, which is for everyone.
"Today in the town of David a Saviour has been born to you; he is the Messiah, the Lord." Luke chapter 2, verse 11.
"For to us a child is born, to us a son is given, and the government will be on his shoulders. And he will be called Wonderful Counsellor, Mighty God, Everlasting Father, Prince of Peace." Isaiah chapter 9, verse 6.