Dating another weirdo? Blame arranged marriages, by Tom Whipple. Why are there so many losers and weirdos on the dating market? Menelaos Apostolou, from the University of Nicosia:

“Personality is central today in intimate relations,” he said. “So you would expect selection forces would tend to optimise it, to shape it in a way that makes people effective in attracting mates and keeping them. It seems this is not so much the case. Why?”

Apparently because in pre-industrial societies arranged marriages were very common, and parents, particularly fathers, are likely to overlook impediments to the character of a prospective in-law to establish a beneficial marital alliance with another family. She expects evolution will take care of it in a few generations.