Today, the Monday after Easter Sunday, is Black Monday, and is terribly, terribly unlucky. Nothing at all should be attempted today, least of all writing blog posts. The reason for this misadventurousness is unclear. It may be that it remembers Easter Monday of 1360 when the English were happily invading France and:
...the morwe after Ester Day, Kyng Edward with his Oost lay byfore the Citee off Parys; the which was a ffoule Derke day of myste, and off haylle, and so bytter colde that syttyng on horse bak men dyed; Wherefore, vnto this day yt ys called blak Monday.
That is a reasonable description of today's weather in London. However, that story is not recorded until 75 years after the event. Black Monday is even less likely to commemorate the day in 1260 that English settlers were massacred in Dublin, as that idea isn't recorded until 400 years after the event.
Or it could be the day on which everybody has a hangover from celebrating the resurrection of Our Lord a trifle too enthusiastically.
This is a different Black Monday that occurred in July