I had a nightmare with my CB750 front brake, which refused to bleed, until I was pointed at this bulletin, since then I bled those brakes and the dual discs on my Z1A with a matchbox taped to the twistgrip, with no problems whatsoever.
A few years ago, after changing the rear tyre on my Heffalump-Dumpaloon, I pushed the rear brake lever down too far and caused a world of pain when the piston got stuck in a part of the master cylinder bore where it wasn't supposed to ever go.