For me it's many things, boot time not even a priority. This is not an invitation to challenge my personal grievances.

If i wanted a monolithic system half of which depends on a single service/library, I would use windows or macos. Basically, I'm trying to avoid vendor lock. I want to be able to replace almost any part of the system on a whim.

I don't care if some user process is not stopping gracefully, I just want to shut down my machine as fast as possible.

When I change a user's groups, I expect that a simple logout/login will be sufficient to apply them.

I want sensible defaults, and systemd has the opposite in my opinion. I don't want to spend hours trying to find one maybe existing setting in some unnecessary system service (which I did not want in my system in the first place but which is shipped in almost every distro) that will probably be deprecated in the next release and I will have to do it all over again.

From what I've seen on social media, systemd's developers and its fandom are insufferable assholes with a superiority complex.

And many many other small and not so small issues that pile up over time (and systemd developers/adopters help with this a lot) and lead to a burnout.

Right now I'm using void btw. And ironically I'm running elogind, which is systemd code. But it does one specific thing in this case and doesn't try to replace the whole os.