My mum used to describe it as making sure the spoon could stand up on its own.
These days, I have friends who order half- and even quarter-strength lattes. When tasked with ordering for them, it usually goes like this:
Okay, and that girl over there? Yeah, the skinny one. Yeah, so, she wants a quarter-strength soy latte…yeah, I know. It’s not even coffee. I don’t know why she doesn’t just ask for a large soy babycino. Anyway…we’ll get a quarter of a shot for her, and could you just put the other three quarters in my flat white? Yes, I know I’ve already ordered a triple…Thanks.