Totally agree with all the negative comments here. Microsoft take note: 386 comments and only 19 likes so far...
"This update is a step towards a consistent experience across apps like Outlook, Teams, and Office.com" - What nonsense. Teams and Outlook are used in different ways (otherwise, why have two programs?). Teams includes a lot of different apps that it might make sense to launch within Teams, so maybe the extra space on the left is needed for some users - I don't find it necessary. But why would I ever need to launch anything other than Outlook functionality within Outlook? There are 5 of these and personally, I only use 2: email and calendar. As many others have said, I have my Windows toolbar to access my other apps. Why try to make Outlook more like Teams? If MS wants consistency, I vote to make the location of this toolbar optional in all their apps ...because not all users have the same needs.
Well, at least this didn't delete all my files like a Windows update did 4 years ago. The bar is very low.