You might be wondering, “Why did humans decide to make a holiday out of the day after a holiday?” Great question, and the answer is pure practicality. In olden times, Easter Sunday was a massive feast and a long church service. People were exhausted, full of roasted lamb and wine, and nursing headaches. They needed a recovery day. So, the Monday became a second holiday in many cultures. It was basically the original “mental health day.”
In the UK, the Bank Holidays Act of 1871 officially codified it. Parliament basically said, “You know what? Let’s just make it official.” And so, the Monday after Easter became sacred for sleeping in. No negotiations needed.