My "obsession" is web performance (#perfmatters), from optimizing the Critical Rendering Path (thank you Ilya), to getting the best from HTTP 1.1, HTTP/2, SPDY, TLS and TCP, in order to squeeze all the bits from servers and clients. In the end it's all about caching properly. Caching is one of those two hard things in Computer Science, and the third constraint in a REST architecture. By the way, I agree with Mr. Fielding in that almost all those REST(ful) APIs out there are using the buzzword "REST" just for marketing, mainly because they are not using HATEOAS. Please, let's call them just HTTP APIs. So if you are versioning your REST API based on the URL, you are doing wrong. Have a look to GitHub API if you want a good example of how to do it well.
Some of the things I love are music, sports, healthy food, traveling, hanging out with friends and Spanish tapas.