I really like the book "This is Lean" by Niklas Modig & Pär Åhlström. I believe the book describes what Lean is, an easy and understandable way. Lean is all about flow.
I like smooth flow. It also applies to traffic. I do not like queues and unnecessary waiting.
The other day I experienced poor flow. Close to where we live there is a road construction, which means that there is only one lane. Therefore, they regulate traffic with a traffic light for a distance approximately 15 m long. That is fine!