WordPress really shocked me a few years back when I finally took the time to read in on what it was capable of doing, especially if you have a decent understanding or object oriented PHP programming, although you can always hack your way through a site with your own code but WordPress has so much functionality built it that i bet even I would not ever get to every part. Its like reading any holy book. You always read it but it seems like you never finish the whole book, or maybe that is just me, but i have an excuse… i read any holy book I can get my hands on so I can more fully understand my friends and clients or the lady behind me at the Starbucks.
My first commercial WordPress site was for a non-profit, IMPACNOW.COM, that I really believe in and I wanted to help them as much as I could. They have a designer give a design for the site and I duplicated their design and gave lessons to the client on how to handle most major issues on their new site and off they went with only two calls about how to fix something they did with their scheduler plugin.
Every time I build a new site for a new company or rebuilding a site for a company with a lesser than what should be marketing their Mom and Pop shops, I continue to reference and add to my lessons learned from all of my previous sites. A public site for just that is in the planning stage at the moment to allow everyone to share their lessons learned from different projects, software/app development, web/web app development or otherwise.
Honk your horn if you love WordPress as a great general frame for all of your needs!!!