I completely destroyed a mechanical keyboard while swapping all the switches. The new switches had two plastic pins that the board couldn't accommodate, but there were white circles printed on the board exactly matching those. So I drilled holes inside many of those circles, replaced a few switches, and tested the keyboard. Most buttons didn't work, so I disassembled it and looked at the other side of the board.
Turns out the fucking chinks printed those circles for no reason, many had traces running underneath.
Some traces I could fix with solder bridges, but a few were damaged in 2-3 places so I had to bypass them with new wires.
Also used the opportunity to cut the cable and solder a USB-C header, which is a win.