Wow that’s gonna be my favorite thread 
When TensorFlow was opensource for the first time in 2015, I got really excited about it, but I even couldn’t compile it after one-week of effort. Then I finally gave up until I devoted one weekend to get up and running with it. Prior to it I was a big fun of node.js and did crazy things like writing really ugly ML code in JS. My first project with TF was a custom clothe color recognition for personal use (I’m blind), so I scraped images of clothing with descriptions from popular ecommerce websites, quickly labelled them with some regex matching color names and trained my model. Everything was great until I naively tested it in the real world and learned (with sorrow, tears and blood) about the challenges of “ML in the wild” vs. a controlled environment, and the necessity that train and test datasets should be sampled from the same distribution.