There's no point in being upset about something that has already happened and cannot be changed; don't waste time regretting past mistakes.
This phrase dates back to the 1600s, with early versions appearing in James Howell's 'Paramoigraphy' (1659). Milk was a valuable commodity that spoiled quickly without refrigeration, so spilling it was genuinely distressing. The metaphor worked perfectly because everyone understood the frustration of losing something precious that couldn't be recovered.
The phrase captures a universal human tendency to ruminate over unchangeable past events, using the perfect metaphor of spilled milk - something that's both genuinely annoying and completely irreversible. Before refrigeration, spilled milk was not just wasteful but potentially meant children going without nutrition, making the original sting of the metaphor even sharper.
Complete word intelligence in one call. Free tier — 50 lookups/day.