"The official protocols define the scope of GDP as measuring all monetised activity between willing parties in a given period. It is a pragmatic definition, but leads to some counterintuitive results. The sale of stolen goods for cash contributes positively to GDP, for example — so theft is good for growth. A parent’s housework and childcare, however, being unpaid, are excluded — resulting, by one recent evaluation, in a $3.8 trillion underestimate of the size of the US economy."

I vaguely remember a similar one around traffic jams as well.

[1] https://www.ft.com/content/b6182440-f21e-11e7-bb7d-c3edfe974...