I’ve found slack super confusing and counter-intuitive in how Cumbersome it is to log in to my workspaces on, for example, my phone. This is because I don’t have a slack account but multiple accounts - one for each workspace and all of them connected to the same email (so for me as a user they’re the same account. come on - Why do I have to sign up every time?)
The UI around this has improved tremendously over the last 6 months, but it is still not great.