I've spent the past 7 years focused primarily on code and database performance.  It's an area that I have a passion for, as well as a propensity.  But what I've found is that its very hard to change the culture of a development environment.  You can teach performance, you can encourage performance, you might see slight shift in how devs think about performance.  But without full management backing and support you wont get long lasting changes in the development culture.  And in the end, you are back to being the "Perf Guy", fixing performance design flaws, after the fact, one by one by one.

Which is why last year I asked my boss to changed my title and responsibilities to more naturally align with the team I was working for.  So now I'm a Computing Research Engineer (vague, I know), researching in the field of Big Data analytics and visualization.

I've found this change revitalizing and a lot of fun.  And given the nature of Big Data (its, um…big) the performance aspects are always ever present.