I think this is a good comment, not immature. I think I understand where you're coming from. I've been a Common Lisp fan for a while. As has been said by others who've used it, even if you don't use it in your daily work, it changes your thinking. I think UML was (is still for a few?) the standard way to define structure and interactions. UML seems to me to have a high amount of ceremony. For something as complex as say, a jet engines control system, perhaps this is reasonable? .. I also like the idea of enjoying "my own quirks". This fits with the dedication in SICP, https://web.mit.edu/alexmv/6.037/sicp.pdf .

  I think that it’s extraordinarily important that we in computer science keep fun in computing

A great idea. The trick is to be able to keep a job while doing that. Looks like you've somehow done that with picolisp!