It is Dutch tradition to have a free day from work directly following Christmas Day.
A bit of history: “The Christmas celebration traditionally lasted for 12 days from December 25 (Christmas Day) until January 6 (Epiphany, the three wise men’s visit to Jesus, according to the Christian bible.) The 12-day feast reflected the winter festivals in Europe during pre-Christian times. The December 26 holiday is now all that remains of the long feast. In the church calendar, December 26 is Saint Stephen’s Day. Saint Stephen lived around the same time as Jesus. He was responsible for distributing aid and support to widows within the church community and was renowned for his preaching skills. He was tried for blasphemy and stoned to death.”
This having been said, the English ‘Boxing Day”* for the second Christmas Day, seems a better explanation. After spending a day with family, eating and drinking and the inevitable inebriated discussions that will ensue, it is probable they will disintegrate into a boxing match?
*For those of you wanting the facts: Boxing Day was traditionally a day off for servants when they received a special Christmas box from their masters. The servants would also go home on Boxing Day to give Christmas boxes to their families.