Virus/Firewall updates, Windows updates, Java updates, repeated forced reboots (four times in total) and playing hunt and peck with all these 'suspicious behaviour' popups, remembering to untick the 'install dodgy toolbar' checkboxes.
I'm starting to feel that a decent package manager is the main reason I continue to use Linux.
/rant
It's like nobody has told MS about cumulative updates. You can install OS 10.9.0 and go straight through to 10.9.5 with a single update.
Maybe this comes from their "enterprisey" system of releasing everything as individual little patches so that IT can decide what to install and what to skip, but it's a nightmare for normal users.
But you're right, it's kind of staggering going from "sudo apt-get update && sudo apt-get upgrade" to Windows'... whatever.
Heck, even most programs in OSX will autoupdate, not to mention Homebrew and Homebrew-cask.
You're still using third-party software for that? There's part of your problem! Getting rid of those would also kill of the "suspicious behavior" popups.
All Linux distros require a restart for kernel upgrades if you want to use that new kernel version. Or are you saying that Ubuntu actually forces the user to restart after a new kernel is installed?