When you just figured out a fix for a bug, your on your way to the fix, but suddenly your co-worker asks everyone in the room "Would you rather be on a helicopter or airplane that lost all power". Then you get into a 10 minute discussion about which and why, and now that bug is permanent.

When a co-worker casually tells another co-worker "We're going to have so many merge conflicts"

When a fellow dev doesn't use their Thunderbolt Display because the resolution isn't as good as their MacBook Retina display. Kids these days....

Almost finished writing some code, then got distracted by devRant. Now I'm back to post about it. MUST FINISH CODING! DAMN YOU DEVRANT!