I once had to make a longer floppy drive cable out out 17 bits of loudspeaker cable ( I`d just towered a 1200 and forgot about the short cable they have!)
Anyway, I "cut and shut" the original FD cable with the speaker wire, then insulated the joins with bog standard cellotape..
Powered up the miggy, up came the purple "insert disk" screen, so I shoved a WB3 disk in..no change.
Powered off, checked the cable and found 2 wires crossed over.
Powered up fine, except there were now icons on the workbench screen for DF0,1,2 and 3 !!
Checked again, found another couple of crossed wires.
I also abused a ZX Spectrum years ago. I found that when it`s powered up, if you run a flat bladed screwdriver up and down the legs of the ROM chip, the TV would start flashing funky colours and patterns ;-)
Finally, I regularly reboot my PC by giving it a hard kicking under the desk, accompanied by shouting 4 letter words at it, but then everyone else does that too, don`t you ??