Whoa, this completely flew under my radar

 Try This at Home

1. Buy a fresh jug of milk.
2. Note that the panel is flat or slightly convex when warm from the store.
3. Refrigerate it overnight.
4. Observe: the panel is now concave (pushed in)—proof it’s responding to cooling and vacuum!
   

    The Bigger Picture

   This tiny dent is a brilliant example of “invisible engineering”—a subtle but essential feature that ensures product safety, shelf appeal, and user experience, all while costing nothing extra to produce.

   Dairy & Eggs

   “Great design isn’t always flashy—it’s often the quiet detail that keeps everything from falling apart.” 

   So next time you grab a milk jug, pause and appreciate that little circle—it’s not a flaw. It’s physics in service of your morning cereal.