Operational needs
Virescit Vulnere Virtus
Even back in the day, when I loved working for FedEx, I went out drinking in my uniform. Now that I hate working for FedEx, I'm embarrassed to be seen in it off the clock.Hmm... Let me think on this one; even put my IBM supercomputer on it.
When you're wearing a company uniform you represent the company. Even if you detest FedEx, it's a brand that many look on favorably. It's fine to go shopping or pick up a pizza in uniform, but drinking seems like a bad idea. Or getting into an argument with someone. For most, drivers are all they ever see of FedEx. If you act stupidly, it reflects on the company. The same company that pays you.