[JacobHarrington]

Anything that breaks my concentration. As a developer, I'm being paid for my ability to concentrate and perform complex thought processes. Anything that impedes that ability costs the company money via the effort I require to rebuild any shattered mental frameworks due to interruptions.

That's one of the reasons I absolutely loathe open office plans. Open office plans are designed with the values of communication and cooperation in mind, but completely ignore that the reality of development work is usually all about how much information you can keep track of while working. If I have to rethink what I am doing every fifteen minutes because two coworkers nearby are taking a foosball break, then I am not being as productive as I can be. Open floor plans are a terrible idea, choosing to save money on real estate at the expense of quality of the resulting software. I've started using it as a sign of a place I would prefer not to work, though with the pervasiveness of this pernicious insult to developer productivity I highly doubt I'll be able to make it a serious filter on any kind of job search since everyone and their misguided brother feels like it's a good way to enhance development team dynamics.