I work on open source software. This means that I work with lots of other people who work on open source software. A neat thing about open-source software is that it basically requires clean code, or at least attention to that sort of thing. After all, labelling your software as open-source when nobody but you can untangle the spaghetti code enough to get anything done is roughly analogous to giving away free soda while charging for the cups. So, people that are ‘good’ at the whole open-source thing tend to care about design.
In particular, I work on GeoServer, a web mapping server written in Java. GeoServer relies on GeoTools to provide database abstractions and other great stuff to help with the geospatial operations, so GeoServer can focus on enforcing security restrictions and providing a decent configuration system and generally bridging the gap between the Web and GeoTools’s Java API. This works out great, since GeoTools can then provide similar functionality to other geospatial applications such as uDig. In the typical open-source way of things, this means that all three projects benefit since the more users an open-source project has, the more developers it will have. (generally speaking).
So, inasmuch as I am defined by what I do, that’s who I am.