Outlook, Outlook Calendar, Teams, SharePoint... I'm honestly baffled by how bad they are. It's like it was made by aliens who only sort of understand what human beings want. And, of course, Microsoft is super selective about their product managers and pays them a ton of money--even though a golden retriever could have come up with a better UX. Literally all they had to do was fucking copy Google.
The online version of Word is astoundingly bad. It can't handle literally the one thing it should be good at, which is collaborative editing. Constantly losing edits when others are editing the same document, even in totally different places. The UI for adding comments is basically hidden and actually viewing all the comments is even worse.
I'm pretty amazed at how bad it is. I could literally do a better job writing the whole thing from scratch by myself if you gave me a year.