I've had a RAM stick fail.

Granted, I've been building my own computer for 30 years and I've only seen it happen ONCE.

But I've seen plenty of other failures:

- Two hard drives -- One got dropped on the floor, so it was no surprise, the other was showing degraded performance and SMART showed some scary numbers and I was able to replace it before I lost data.

- One GPU, replaced under warranty.

- One AIO water cooler, replaced under warranty. Somehow, the water vanished from the loop. I'm guessing a microscopic leak that evaporated as fast as it leaked.

- Two power supplies -- One randomly exploded. Just started making popping noises and shooting sparks out the back. At autopsy, I determined that the fan failed (it was hard to spin manually) and it overheated. The other was just being overloaded. I had just gotten a new GPU and the PSU wasn't big enough for it.

- Several case fans.

Never seen a CPU or motherboard failure, even when my AIO water cooler was failing and my CPU was constantly at thermal limits. Never had an SSD/NVMe failure.