The Metric System
Having any machine with both is a huge pain and the Manufacturer should be shot!
I work on commercial restaurant equipment and some still come with both, make up your F'ing mind. I understand suppliers and cost are involved but why is it field technicians have to deal with this crap and carry a heavier tool pouch.
My auto mechanic son still sees it too, he was brought up on metric and prefers working on SAE/Imperial cars.