Yeah, one of my learnings that took a bit is that as much fun as learning the classic lispisms like car/cdr/cadr/cadar/caadr/etc was, with their long history and particular "early punchcards typing efficiency" at some point it is useful to learn the newer sides of the language that could afford entire-words and cool modern DSLs like loop.
My push into Common Lisp was a current revision of a classic AI textbook that mixed up usage of nearly the complete history of lisp because some of the examples presumably dated to the 1960s/1970s with moderate adjustments to make sure that they still compiled in SBCL or the like, so it was a natural lesson from that textbook. Maybe not the best way to learn Common Lisp, but that was an interesting semester for me. (I and the few other people in the class that semester decided to learn Lisp by choice for the class and I think I was the only one to also decide "I'll do every assignment with implementation language choice in Common Lisp this semester", which was most of my classes, just to keep grad school interesting.)