There is one, super-missing thing in HA, that would make many user’s lifes easier - easy setup of schedules. I really believe this is the most common automation use cases. The more detailed use cases for this include heating (time range per day, temperature-driven), lights control (time and lux sensor-driven), water sprinklers / valves control (humidity driven). There’s a custom component for this with a quite good UI and UX (Scheduler card/custom component), but would be great to see it integral part of HA.
Of course all of this may be done using HA automation, but in most cases this is awkward from the UI point of view (not easy and intiutive config change, no clear schedule overview UI) and I understand the goal is to make it easy, quick and user friendly.
Sample UIs for this, posted in the Feature Requests section of HA Community, which propose even better UI: