A few weeks ago, a (somewhat) seasoned coworker mentioned that some people -- especially higher-ups -- pay notice to the order in which coworkers are listed on email recipient lists. The idea is that, the more important you are, the closer you should be to the front of the list. Also, he mentioned a kind of etiquette when listing people in CC's. He said that people may get offended if they're not "listed properly".
Is the company I'm working for just overly egotistical, or is this actually common knowledge/practice?
How exactly should individuals on an email recipient list be added/prioritized when considering their position in the company and their relevance to the nature of the email?