It's all about perception. I had a friend who used to run a restaurant in NYC. They used to get complaints every once in a while about the serving size for their wine by the glass.
The solution? Smaller glasses of course. Complaints dropped to zero.
The solution? Smaller glasses of course. Complaints dropped to zero.
Sadly, wanting good things leads to a lot of stress, at least in the US. (Go to Target sometime. Is there anything there that you couldn't get a higher-quality version of on Amazon for less money? Nope.)
Expectations? If you put a big cup in front of me, I can expect you to fill half of it, fill it completely or anything in-between. If the glass is small, I expect you to fill it to the top, no uncertainty.