To cry over spilled milk is to remain upset about a past loss. Example: "We came so close. Really. We almost won that game!" Reply: "There's no use crying over spilled milk."

When milk has been spilled, it is wasted and cannot be used. There is no reason to keep complaining over the loss. Note that either of the words spilled or spilt can be used. Example: "Well, the car is ruined and that's too bad, but there's no use crying over spilt milk. We're just going to have to get a new car."

Crying over spilled milk is not useful because the thing is already lost. Parents often tell their children to stop crying over spilt milk. Example: "I can't believe we lost my favorite toy!" Reply: "Oh, stop crying over spilled milk. You have other toys to play with."