1. don't get emotional or don't panic (over a small incident)
don't cry over spilled milk, it's easy to fix
The idiom 'don't cry over spilled milk' is a reminder not to overreact to small problems that have uncomplicated solutions. You will often hear this idiom used in a situation where someone breaks or destroys something and is overly apologetic or upset. This is an idiom you can hear in professional and social contexts.