I do recall difficulties with this in the beginning (the first few years in my case ;-} And I still find old LISP code (the one where symbols were still capital

I do recall difficulties with this in the beginning (the first few years in my case ;-} And I still find old LISP code (the one where symbols were still capitalized) hard to parse. With modern (say, since the 90s or so), well written style where the depth of the expression is indicated by the indentation, I trust that the editor indented correctly, which allows me to forget about the parentheses. I wouldn't attempt to find a syntax error in a CL program w/o an editor supporting the language. Above might be interpreted as a case for a language with semantic whitespace and w/o excessive parentheses, e.g. like Python, but there I find it all to easy to introduce subtle bugs during refactoring.