I can't think in anything else in which I worked that hard and for such a long period of time, at least by my own without any help at all. That project is Chevereto V3.
When I started to develop this version the goal wasn't remotely close to the final working product (you can see it here) and to be honest, I've always loved to work in Chevereto more than anything else, with the exception of Junkstr, and soon as I started to work on this third major release I decided to highly increase the bar regardless of the time and the complexity of the project.
I don't know if you feel or see the same as I do but for me it is an amazing system and I'm so proud of it and I'm happy to keep feeling this when I release something.
Long life to the #1 image sharing script in the world.