Anyone who thinks that these three have the worst UI possible has never had to deal with a really bad UI. Try Sharepoint on for size. Or Azure. Or Jira. And there's likely still way worse stuff than those.
Microsoft stuff is always ... very consistently microsoft lol
it almost feels like they tried too hard to make it looks simple on the surface, and then ended up shoving all the rest randomly in drawers/cabinets/boxes/wherever...