A lot of people in the coding community talk about continuous improvement, deliberate practice and so-on - but when they talk about their current practices it's almost like they 'sprang fully formed from the loins of Zeus' because you don't hear about how their opinions changed over time or what they learnt recently.
Every now and then though I go to a talk, or read a book, or talk to someone and they open up a bit more and I find that I learn a lot from these insights.
So, if you had to pick one thing from the last 12 months that you learnt what would it be?