I thought I'd mess around with WordPress and create a plugin or two. I ended up creating SEOBudd, a SEO stats plugin for WordPress. It retrieves stats about your website, such as average load time, social media mentions and incoming search words. It' has been approved and is now available for purchase on CodeCanyon.
I must say, working with the WordPress plugin API was no fun. Everything felt just so clunky. Unless I'm missing something, you're almost forced to use global variables and procedural functions. The amount of things you can do with the API is quite astounding (the shortcode functions are quite interesting), but the online documentation is difficult to navigate. I finally found the function reference that lists every available function after some searching.
At first, I opted to using my own CSS for the admin panel of SEOBudd. Of course I didn't really investigate more and ended up with a design that didn't fit WordPress at all. After some searching, I found this page "How To Design And Style Your WordPress Plugin Admin Panel"; you can inherit the administration CSS rather than using your own. I found that his created a more native experience.
Another function I found interesting was the options functions. Instead of creating your own database or table, you can let WordPress handle it for you. No need to worry about data types either.
Though it may have not been very much fun, it was easier, if I may say, than creating a Drupal module. I think that Drupal has a much more rigid structure that guides you along.
Anyway, I don't expect too many sales of SEOBudd, so I'll probably put it up on Github sooner or later.