I know it's a classic "don't blame your tools!" situation, but the ability for even moderately-experienced programmers to accidentally build high-incidental-complexity tooling that becomes a nightmare to re-learn once you've lost your mental model of the program is, in my experience, unique (and frightening).
I once spent weeks trying to get a LabView-based tool up and running that a senior engineer in another section had written. Sketching out the relationships between components, documenting I/O, etc. After finally giving up the ghost, I went to that engineer for help. After spending hours (like, 5-6 hours, not 1-2) sitting next to him in my lab, he said "yeah, I'm not really sure what I was doing with this...", and proceeded to need to take the entire program back to his desk for nearly a week before he could finally explain how it worked.
This situation wasn't a one-off; it's happened with nearly every non-trivial codebase that I've ever touched that used it. In my experience, LabView is really fantastic in only two situations:
a) Very simple GUI-based DAQ tools that the person who wrote the program, and them alone, will need to use
b) Complex tools that are owned by a team of engineers who have written LabView for years and will now be dedicated exclusively to those tools