I got a used computer case in a second hand hardware store and it still has the sticker with the specs of the computer they wanted to sell it with on it. It was going to be a moderate to shity pc. I built an absolute computing monster in it (i7 6900k, 32GB ram, 23TB storage). I like having visitors over and telling them this is the primary computer I use to do my high particle count fluid simulations and little bigdata projects with.

Old story, and yeah, it's all true, I shit you not!

So here I am at about age 11 (more or less). At the time, I had an almost brand new 333MHz beast, with 8 MB RAM, 2 (!!!) MB video card and (I think) about 300 MB of storage (yeah, I'm old :)) ).

Connected to this monster was sitting a 14" CRT monitor, mechanical keyboard and a 2 button, ball "powered" mouse.

There was no optical tracking tech at the time.

One evening, I notice my mouse starts lagging. Test it to see if Win95 is stuck. Nope, just mouse problems...

Fiddle with it a little, and at some point it stops working at all.

My room was dark now, so I got up to turn on the lights, sat down in front of the PC, and moved the mouse by instinct.

Surprise! It's working again!

My brother comes in and turnes off the lights. Mouse non responsive.

I tell him to turn them on again, mouse works again.

At this point, we were both scratching our heads at this mystery...

I decided to confirm it again using a desc light.

Conclusion: my 2 button, ball tracking, non light sensitive mouse was working only if light was shining directly oh it AND on my 14" crt monitor at the same time!!!

To this day I have no ideea why.

I kept them both for posterity, and they are still there in my parent's attic.

Fin.

My friend's desk. He has a monster PC.

I had a 1Tb external hard drive on the corner of desk (My fault, i know, but at that time i didn't have a lot of space), i used it to keep mostly unimportant things like game files, VMs, movies and stuff like that. Once i was streaming a movie from the pc to the tv in the other room, suddently the tv disconnected, i went to the pc room to check, and i found out that the evil monster that lived in my house (the cat) dropped it off the desk.
The hard disk died and brought all its files with it, luckly i had backups for most of the important files, but i had to download again around 300GB of stuff.... with my slow internet.