Some of your stories make me cry (whole A3000 towers in the dump)!
In the mid-to-late 90s, when Amigas were starting to show their age and were beginning to be out-performed by Macs and PCs, I occassionally got frustrated/discouraged and came very close to selling my A2000 setup to get something more "up to date". Thank goodness I didn't, as those Pentium IIs I thought were so great are now worthless.
Now that the old Classic Amigas have been totally surpassed (speed wise) by modern PCs, etc. I have gained a whole new type of enjoyment from my Amigas (retro computing). I enjoy them for what they are and the unique things they can do rather than trying to compare them to modern PCs.
However, in terms of the worst thing I have ever done to an Amiga: I once plugged a Commodore 128 power supply into an A500 that I purchased from a Thrift Store (which was missing its power supply). The power LED went on for a couple seconds, then there was a *POP* inside it and the smell of burnt ICs. Uh oh. I was sorry to have ruined an Amiga, but I only paid $2.99CAD for it, so no financial loss (and it's still good for some spare parts).