* Build difficulties.
* Hidden dependencies.
* Multiple and conflicting sources of configuration information.
* Lack of documentation
* Incorrect/outdated/stone-cold lyin' documentation
* Mis-named executables, configuration files, variables, constants etc.
* Lots of global state
* Inconsistent and surprising design choices.
* Console noise inundation.
So, the supposed "10x engineer" simply knows a few paths through this mine, while the rest of you just keep triggering them with almost anything you do.