Wordpress kind of makes me realize how incredible PHP is. It's a 'program of pages.' Which can basically hot swap update itself as it runs. You can download plug-ins in the control panel and extend the functionality of your site instantly. I still get mixed up trying to wrap my head around it even after 15 years of using it. It's a program that exists in different files that can be updated individually while the program itself is used. Most of the 'state' is temporary or stored in dedicated memcaches or databases. It makes you wonder what if other applications were written in a PHP style structure - what would that be like?