See that glass up there beside the wine bottle?
Here's another view of it beside one of our usual wine glasses.
And here it is full.
The lesson to be learned here - as predators our eyes are designed to catch moving objects, but not to weigh or measure them.
Don't believe me? Then watch the video.
Bottom line - if you're trying to watch consumption, don't expect your eyeballs to help.
[And a special thank you to the patient who so kindly brought me the glass]