I think what pissed of many users was that the update messes with your settings once again, and that Cortana cannot be disabled anymore without messing around i

I think what pissed of many users was that the update messes with your settings once again, and that Cortana cannot be disabled anymore without messing around in the registry. Another point was that they forgot to turn off some debugging option they had presumably activated for their developers which opened up a big vulnerability.