On reflection I am sure the fact that both he and I had backgrounds with solving performance problems, forcing us to dig into the details of big-O is why we had

On reflection I am sure the fact that both he and I had backgrounds with solving performance problems, forcing us to dig into the details of big-O is why we had similar experiences. Mix with what is probably some standard questions inside Google and it illustrates the problem I was thinking about. That is one of the better videos I have seen on the topic, so thanks for sharing it.