Personally my only gripe with systemd is that the systemctl and journalctl commands are cryptic and unintuitive. Every time I have to use one (which thankfully isn't often), I have to spend 5 minutes reading man pages to remind myself whether -u is "user" or "unit", what the difference is between a "unit" and a "service", etc.
I imagine this is what non-developers feel like when they're forced to use git—having a whole pile of unfamiliar vocabulary and syntax thrown in your face when you're just trying to do one simple thing.
The first step after you untar is always "open the README and look for build instructions."