heck of it
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.

[TahlilGaran] English Idioms Dictionary ▲