It's hard to build an oscillator

When I was a kid, and didn't know much electronics, I was building a synthesizer kit. I only had to put the components in the right places and solder them, and maybe do some troubleshooting.

My sibling, who actually knows electronics, looked at the complexity of the oscillator circuit, and said something implying that it's overengineered.

They left for a few minutes, and came back with a much simpler oscillator. We plugged it in and it sounded pretty good. Then as it heated up, it started drifting wildly out of tune.

Yeah, it's hard to build a musically useful oscillator, that stays in tune and tracks well over many octaves.