Oscillators are supposed to oscillate but when you want them to, they don’t resulting in debugging.
Amplifiers can have a big phase shift and gain which fulfills barkhausen criteria which is the fundamental requirement for something to oscillate. Oscillating amplifiers are usually a very bad problem because it trashes the signal you are amplifying and tends to suck up a lot of power.
Fuses take a glacial amount of time to blow compared to an integrated circuit. When something goes wrong the IC blows up way before the fuse goes.
With respect to oscillators, the old saying of “amplifiers oscillate; oscillators don’t” comes to mind. Electronics is a cruel and unforgiving field.
Also burn myself and let the magic smoke out and I’m apparently qualified in this field. Go figure :)
A broken Tektronix scope will teach you more about electronics than a textbook too. I think I’ve had about 20 of the things over the years.