Hrmm...
Making extra-thin-wall sockets for tight holes.
Grinding the beveled end off sockets for thin nuts flush with surfaces.
Re-shaping the tips of pullers, etc, for fitting in tight spaces.
Brazing an extension to a drill bit.
Cutting a long socket down to make a medium-length socket.
I know I've done more, but that's all I can think of at the moment.
--Bushytails