I had to use a macbook at a previous employer. It didn't live up to its reputation of being user-friendly. The alt-key didn't work by default on the terminal emulator and I had to enable it in some menu after googling the problem. The infamous command key was just annoying and i wish i had a real control key.

I also hate how they stubbornly refuse to put a second button on any of their trackpads/mouses (mice?); the fact that they implemented a version of right-click by clicking with two fingers shows that it's needed and that they abstain from it out of pure stubbornness. The one saving grace for this is that they let you plug in a USB mouse, and the right-click will work as intended but I'd still prefer it if it was build into the system. In addition to being counter-intuitive, the double-click would also prevent problems for users with disabilities. Also could prevent problems for gamers since FPS games generally assume you have at least two mouse buttons, although to be fair touchpads don't work well for gaming in any case so you'd probably still need a USB mouse for gaming even if they did have the right click.

I also found the lack of ethernet frustrating; I had to use a stupid over-priced thunderbolt/ethernet adapter to get online. Since this was a laptop, that meant I had one more thing to carry around and one more thing to plug in every time I used it.

The touchpad also had some durability issues; after a couple years it stopped clicking when I pressed it. It still worked somehow but it didn't have that crisp "click" feeling that you get from tact switches and it stopped making noise when i pressed it. Still usable but it felt uncomfortable.

I also wish they had something similar to that desk dock that lenovo thinkpads have. I wouldn't really fault them for not having this since most PC laptops don't have it either (in fact, I think I've only ever seen it on thinkpads and I'm not sure if they all have it either) but it's an amazing convenience when you work in a cubicle to just be able to drop your laptop into the dock and have your monitor, keyboard, mouse, power, speakers, and ethernet all connect through that one bus.

One last problem is their batshit insane decision to deprecate OpenGL while not supporting Vulkan either. This is less of a usability problem than a general platform problem, but I develop an open-source application which has 3D graphics, and the lack of any cross-platform graphics API is a dealbreaker for me, both as a user and as a developer. I just can't work without OpenGL/Vulkan. I could port my program to Metal if I really wanted to put in the extra effort to support apple, but even then I wouldn't be able to use a macintosh as my primary development platform because I wouldn't be able to test the OpenGL backend that my program relies on for every other platform. Their decision to deprecate this absolutely unprecedented; even M$ at the height of their monopoly in the late 90s still supported OpenGL; they could have dropped it and only supported DirectX if they wanted to lock developers into their platform but they chose not to. Apple seems to want to lock customers in to their platform at every level, and at this point they're worse than M$ ever was.