An excellent question. I'm sure others will be able to answer more at length, or link to good articles elsewhere that do. I'll try to do it briefly and incompletely here.

Perl 5 has a relatively simple model around which it builds everything else. That means that you can start unravelling it from some end, and the more you learn, the more you'll find that the pieces "fit together".

You'll find that Perl 5 doesn't get in your way when you want to accomplish a task. Want to name a subroutine "42"? That can be arranged. Multiple inheritance? Sure. (But don't do that.) What if you want to make a subroutine that creates (anonymous) subroutines? No problem.

Like all other languages, Perl 5 has idiosyncrasies and pitfalls and dark corners, but all-in-all it compensates well for those by being really flexible. It goes a long way to please you, the programmer.