The origin is even funnier. You see, the USSR documentals had a rather interesting tropes to them. So, in one particular parody, where a presenter accidentaly meets an elderly man who JUST happens to be a former pacemaker. They JUST happen to keep running into relevant things or people. Said man JUST happens to like music and JUST happened to bring along a violin so he plays it. And Then they JUST happen to run into piano in bushes. "There just happens to be a piano in bushes, so I'll play it".

Pfffft, that’s kind of amazing. X3