SEO & SEM
I love SEO. I love everything about it. The main thing is competition - I like to compete and love too see concrete and clearly measurable results.
After 15+ years in SEO field, usually I don't need glamorous SEO tools to figure out what is going with a website and why it is doing bad. Of course, I am using everything from the pallete: Google Analytics for better tracking and reports; Google Tags for conversion tracking and remarketing, MailChimp for email marketing, SeoMOZ, Raven Tools, Ahrefs, Screaming Frog... Those are the tools I am using from their begginings.
For ten years I was part of Joomla! and I deeply understand how one CMS work. I worked with other control management systems too: ProcessWire, Drupal and WordPress, including ecommerce types like Magento, OpenCart and PrestaShop. HTML and CSS are just funny part to play with.