What was Black Sabbath's biggest blunder?

What was something Black Sabbath did or was a part of that you think was a huge oversight and should never have had happened?

Some examples:

-Allowing Patrick Meehan to control their money?

-Firing Ozzy?

-Not recording their session with Led Zeppelin?

-The Live Evil mixing debacle which caused RJD and Vinnie to leave the band?

-The original mix of Born Again?

-Continuing the band's name when Tony was the only original member?

-Playing in South Africa during Apartheid?

-Not recording a new studio album during the late 90s/early 00s?

-Not including Bill Ward on 13?

Or was it something else?