This expression goes back at least 360 years. English historian James Howell used the phrase in a book called “Proverbs in 1659” — “No weeping for shed milk.” ... Whenever milk was spilled, it was considered to be nothing more than a little extra offering to the fairies and nothing to worry about. Regret is a painful feeling. However, it is also necessary to learn from your mistakes and move on. It is important to apologize to people you may have affected and to make things right for them. However, you must be careful not to spend too much time dwelling on the past. No matter how you say the proverb, “don't cry over spilled milk” or “it's no use crying over spilled milk,” the phrase means that there's no point in being upset over something that has already happened and cannot be changed.

National Don't Cry Over Spilled Milk Day is observance annually on February 11!

We have been unable thus far to find the creator of this national day, but we will be sure to keep you posted.