Back in the days where my pops would have to explain computers to me, ( instead of the other way around like nowadays... ) the most effective way to fix our old A500 was to smack it a bit! I was lil back then, so I couldn't hit it hard, really. But it worked most of the time, solving weird freezes and several odd glitches.
A few months ago I got that same old A500 back from a friend my pop gave it to years ago. Decided to clean it up a bit an opened it for the first time. The smacking helped because of some funky dual-kickstart solution involving some ribbon cabling, some soldering and cramming 5 or so sockets on top of one another... I think...
I loved those things back then. No matter how hard I hit my computers nowadays, they all still suck compared to Amigas. As for the stupidest thing that happened to the A500? My dad gave it away and bought a 486 instead. I think I redefined the word "angry" that day...