Women have to wait longer than men to get served in coffee shops, according to this new paper. It estimates that, even controlling for women's tendency to order fancier things, they have to wait an average of 20 seconds longer than men.
In shops with all male employees, the average wait is 37 seconds longer. But in all-women shops, it's an insignificant seven seconds.
This could be because male employees want to spend time flirting with female customers - though this is controverted by the fact that people of below average appearance also have to wait longer (albeit only slightly). Alternatively, it might be because women are thought (rightly) to tip less. Or it might be that staff think male customers have less time to wait.
Whatever, there's a serious point here. Discrimination can exist even in competitive markets, contrary to what Gary Becker predicted. There's more evidence here (pdf).