Overall, the big issues I have are that when it breaks it does so unpredictably so I can’t learn how to do things right.

1. It was unclear to me for a long time how to find files correctly (it still kind of is unclear). Our institution uses SharePoint for some things, Teams for other stuff, and some folks use OneDrive. It’s hard to know how these things talk to each other–sometimes this data is actually shared between those ecosystems and sometimes it isn’t. It’s probably how some people are settings things up, but I blame the software for making those relationships somewhat obtuse. My understanding is that everything on the backend is actually SharePoint and Teams and OneDrive are just different front ends with different permissions structures. That has helped somewhat but it’s an imperfect understanding.
2. Joining Teams meeting links from other institutions is fraught with problems. If I have a Zoom link from somewhere else, I click on the link and the meeting starts. That’s it. I click a Teams link on a not-work computer and it can be difficult to open (SSO something something probably). So instead I’ll open in browser, which may result in a “browser not supported error” on every browser (including Edge). Even if I can get in my webcam might not support backgrounds. Or the microphone/camera selection I made in browser permissions is ignored by Teams. Any one of these events occurring appears to be random, so I have to plan on a few extra minutes before Teams meetings to log in.
3. Notifications don’t go always go away when seen. I sometimes have to click out if the window and click back in.
4. Incomplete markdown support (let me copy/paste a table from pandas!)
5. This is dumb, but gif selection sucks. They must do some sort of aggressive filter for work or something, and maybe that’s an enterprise decision. But if I want to communicate exclusively via gifs that is my prerogative, thank you.