In <i>increasing</i> order of importance:

1. Interruptions and context-switching

2. WTFs that are now everywhere, in language syntax, in libraries, etc.

3. Incomplete or inconsistent libraries, with unexpectedly high learning curves (e.g. due to lack of good documentation), recursive dependencies, etc. Half the time goes into just wiring things together, whether code or data.

1. Music that's not trancey enough to help me get in the zone or quiet enough that I still hear the office. Hard to find good music that hits both sweet spots.

2. Library incompatibilities (Eclipse I'm looking at you).

3. No code search to find specific methods across the entire code base.

4. No here's what you were just working on list (especially important if you get context switched out to go fix fires and forget exactly what you were up to).

This might seem trivial, but having so many editor tabs open that you can't see the name of the tabs anymore. Clicking one by one through the tabs to get to the one I want can break my concentration and throw me off.

Answering market-research posts on HN. ;-)

Hey, it's true. I was happily coding along until I felt the need to check HN.

Thanks. I was trying to stay away from the external factors like email/internet as those are pretty obvious and focus more an issues when you actually working and not being distracted :D.

1) Lack of good Unit tests. 2) Stupid colleagues. 3) Bad food.

Builds that take a long time

Yeah I mean when you are actually coding though. I guess a better question would have been what "mental challenges" do you experience while actually coding.

> ... a specific issue that slows productivity while coding?

Not periodically getting up and moving away from the task for an hour or so, to gain some perspective on the project and a bit of distance from the minutiae of coding solutions to many tiny problems.

Any number of times I have taken a break from coding, only to realize I was crafting the wrong solution by being too immersed at too low a level in the code.