Many restaurants serve their shakes and malts in glasses that are too small. Instead of putting the entire milkshakes in glasses that can fit the whole drink, you get this undersized thing, and then they bring out the metal mixing cup with another 2/3rds of a glass full of malt. It makes you think that you're getting a better bargain - as of you are getting almost two shakes for the price of one.
The problem is that the extra shakes sits in that metal cup and it sometimes turns into a big frozen mass of milkshake, and when you pour it into your glass, if you forget to stir it first, it all comes out in one giant glob. And a bunch of it lands outside your glass. So unless you are the kind of pig who sucks milkshake from the tabletop, you waste some of your milkshake. Next time, why can't they just put the entire milkshake in one nice big glass, so we can drink the whole thing? There ought to be a law.