A (one presumes billed as “seamless”) update process that requires clicking yes to a dialog box, confirming a UAC operation, and reading a licence agreement.
I think the most egregious step is that every minor update should require accepting a licence agreement. Do they patch not just the software, but the software licence?
Software updates represent probably the biggest backward step in usability the consumer desktop has taken in some time – it’s so hopelessly fragmented, and the inappropriate arms race, the drive to “make our updater bigger, more noticeable, and more frequent than the competition’s” doesn’t help.
(This is one of the areas where for all their other usability issues, most Linux distributions have consistently got it right. Updates are collated through the package management software, and not by every single application installing its own separate update daemon.)