See: DEVIL OF IT.
{n. phr.} 1. The worst or most unlucky thing about a trouble or accident; the part that is most regrettable. * /Andy lost his notebook, and the devil of it was that the notebook contained all his homework for the coming week./ * /When I had a flat tire, the devil of it was that my spare tire was flat too./ 2. Fun from doing mischief. - Used after "for". * /The boys carried away Miss White's front gate just for the devil of it./