I would guess that he was mostly pissed that things "just changed" without being asked. While these sort of things like the up arrow seem like a no-brainer to many here, showing up for work on Monday and having everything
just be different sucks. It's a bad experience, and I can't really blame him for being annoyed.
A lot of times people would be a lot more receptive if you show them "hey, you can use the up arrow like so if you want!" Then they can choose and adapt at their own pace if they want to, and they're in control of their own systems.
