My comment history here is full of complaints about MS Teams, the chat app. It suffers from the "re-use every existing MS tech" problem. Building it on top of SharePoint I'm pretty sure resulted in it's top problems over the years (some fixed): - search sucked - can't scroll back to old messages - couldn't do private channels - the very concept of 1:1 teams to SharePoint site, resulting in a millions teams when all you really wanted was a channel - can't rename teams or channels - couldn't do private channels

I'm sure many more I didn't catch. These are all observations from outside, I've never worked at MS