Carl and Richard talk to Adam Tornhill about his work understanding the psychology of programming. The conversation starts out with some thinking around getting into "the flow," being able to focus effectively on programming. Adam then digs into where bugs come from and the role of complexity in code. He has been studying code repositories to determine where bugs are likely to appear based on the idea that complex code changes more than simple code. The discussion also explores the idea that while coding parallel code is challenging, parallel development is even harder - can you really get multiple people working on the same project at the same time? You think you do, but do you really! Time to study your source tracking system!