I was thinking about this recently, what's the dumbest bug you've caused yourself?
I'll go first.
More often then not my code won't work because of a rampant letter 's' somewhere in the code. 'Undefined variable s' etc.
The reason? Hitting CMD-s to save a file and letting off CMD too early...
This series of posts document a high-level process to use when planning a modern web application, from project organization, collaboration considerations and tooling choices during development, all the way through deployment and performance strategies.