Oh boy, JCL... we had a couple of JCL gurus who understood it but the rest of is just kept hacking away at existing templates.

And CICS. But even worse than those two was a 1980s IBM business language called CSP ( Cross-System Product ). If you can imagine COBOL with all its limited expressiveness removed. I used to be elated when I opened a member and found it to be COBOL or C rather than CSP.