Why build your own blogging engine when so many open source solutions already exist?

Blogging engines are a simple enough concept that it might well be faster to write your own than to understand, configure and patch an unfamiliar system.

I originally wrote mine in 1999-2000, when there were very few options (if any). It works, so why not keep using it?

Because it's fun? And all the options suck in one way or another?