I had never heard of queueing theory until I read about it in a supply chain management textbook, and would have appreciated being at least aware of its existence much earlier than that. This is light, but it's a great way to introduce the topic to people who have never been exposed to it.

By the way, I also worked in a supply chain management department of about two thousand people for three years and I never heard anyone else mention queueing theory while I was there, so now I really wish at least this blog post were required reading for everyone in that department.