The Aのなせるわざ thing is a little awkward but certainly not the potential. Like yudantaiteki said, なせる is an old word that shows something has been done. Kind of like the English present-perfect tense. Daijirin defines it as "おこなった。引き起こした。" with the example sentences of 「自然のなせるわざ」「群集心理のなせるわざ」
「Aのなせるわざ」is basically an idiom meaning "It is precisely because of A that ~~ came about." So in the above two examples..
It's precisely because of his strong will that he won't lose. (His not-losing is a result of his strong will.)
It's precisely because of X's efforts that ~~ came about. (~~ is the fruit of X's labor).
Googling "*のなせるわざ” brings out quite a few more examples.
「米国の安倍批判は嫉妬心のなせるわざ」
The USA criticizes Abe because they are jealous.
「若さのなせるわざです。(それから15年。私もずいぶん大人になりました。)」
It was because I was young. (But now, 15 years later, I've become quite the adult.)
「自殺は無知のなせるわざ」
Suicide is the result of ignorance.
afterglowefx wrote:
What's the easiest way to express that something was done accidentally? I know しまう can be used to express unintended circumstances, and many verbs have forms that express that something was done by chance, but what if I just want to say, "Sorry, that was an accident!" after, say, knocking down a huge stack of Uno cards on a student's head? Thanks!
You can say something like "わざとじゃないよ!” or "そのつもりはなかった” for things that happened accidentally. But I think the most generally Japanese response in this case would be to just apologize and ask if they're OK. That should get across the point that you didn't do it on purpose. If they accuse you of purposefully dumping cards on their head you can pull out the "わざとじゃないよ!"