I love puzzles and when not doing this, I work as a webdesigner building websites for companies. A good webdesign is the key to having a succesful webshop or website. It's also a puzzle you need to solve in order to have the perfect combination of a modern webdesign and good usability and seo.
My biggest puzzle I have made is 4000 pieces which took several months to complete. It really tested my limits and it will be a while before i try on such a big project again.