The shape of the glass affects the speed of beer-drinking.

It's a study!

People drink more quickly out of a curved glass. But not for a soft drink. We're talking about beer:

While it took around seven minutes for people drinking from a curved glass to polish off their half pint, it took 11 minutes for those drinking from a straight glass....

The researchers thought that curvy glasses made it harder to pace drinking because judging how much was in the glass became more difficult owing to its curved shape.

It's because it's alcohol that people try to pace themselves. And apparently the curves are confusing.