A few years ago I got to experience the pedantic nature of Air Force uniform culture. I was a civilian contractor wearing AF ABU. I started the day wearing a t-shirt, morning shirt (kinda like a warm-up jacket), and ABU blouse. In what appeared to be a somewhat casual office environment, I removed the ABU blouse when the office got hot. A JO told me that the morning shirt couldn't be the outermost layer. So much for layers.
A few days later, I wore a t-shirt and the sage fleece with branch tape (US Contractor) and name tape. I knew that I couldn't shed the fleece and wear a t-shirt in an office environment. Well, there was a VIP arriving and the same JO asked me to remove my fleece. He was expecting an ABU blouse underneath, not my t-shirt. He was not pleased.
The rest of the contract, I decided not to play and just wore my Navy whites just to get salutes from that JO.