alt text
Comic strip of a ghost and a person with the American flag pasted on the head. The ghost repeats “Boo!” in the first three panels without getting any reaction, but when it in the fourth panel says “kg, cm, km, °C” the American gets scared and screams “AHHHH!!!”.
Edit: fixed alt text
Depends on context, IMO did/mm/yyyy is the most natural when writing some text, but partial ISO yyyy-mm-dd is ideal for when naming files and directories, makes lexicographical ordering follow chronological order.