I’ve written multiple Zsh plugins, so I’ve gotten familiar with a lot of Zsh’s features. I’ve probably read every line in man zshexpn twice by now having referenced it so much.

Zsh expansions can look gnarly because parameter expansion forms can be nested. Where Bash has to do:

tmp=${foo%$suffix}
len=${#tmp}

Zsh can do it in one:

len=${#${foo%$suffix}}

Once you add PE forms which don’t exist in Bash, parameter expansion flags, array subscript flags, globbing qualifiers and modifiers, you can get something which looks absolutely unreadable.