Back in 1984, when I was living in the Netherlands, I was lucky to visit the tiny Gulpener Brewery in the city of Gulpen in the Limburg province. There, in the tasting room, the brewmaster taught those of us visiting that a properly poured glass of beer should have a head of foam equal to the height of two fingers side-by-side.
Here, in the States, we have a tendency to not want any head on our glasses of beers since the foam is viewed as waste. Apparently, the Japanese actually like a really foamy head on their beer hence this product found on the Gizmodo website:
Self-Frothing Beer Mug Grants Your Brew the Massive Head You Never Wanted