Changed how I think about a lot of stuff, made my design process a lot more rigorous, and my projects more successful.
"The Shift: UX Designers as Business Consultants" Davide Casali-Interaction14
Fred George - Programmer Anarchy
Ian Cooper: TDD, where did it all go wrong.
(All my objections to TDD expressed far more fluently than I could).
Not technical related but...
The key to becoming a super-profitable creative agency
(though still working out how to apply it)
I have a large "To Watch" list kept in open browser tabs - someone must have built an app to better manage them? So I can say "All the videos on http://www.microconf.com/videos-2013.html" and have it add them to my watchlist.
Any talk by Bret Victor.
https://www.youtube.com/watch?v=JxAXlJEmNMg (Browse the related videos to see the others)
He actually speaks about a potential alternative present. ;)
Absolutely ruined the box I was thinking in.