Unless it is not overly complicated, it is possible to write regular expression in such a way you can later on understand what you were thinking at the time you

Unless it is not overly complicated, it is possible to write regular expression in such a way you can later on understand what you were thinking at the time you wrote them (using the extended syntax available in Perl and elsewhere - it allows you to break up the regex into multiple lines and embed comments). It takes a little more effort, and one does not get the "look how dense it is"-rush, but I guess the same can be said for all code. There is a point where it breaks down, but there is a range of text-matching/extracting problems where regexes are both useful and - if one makes the effort - maintainable.