Windows is very lazy about reboots. Minesweeper changed? Better reboot.
Chrome also got infected with this laziness. It used to be that you had to restart chrome once a month, now it's almost every day. Among many other reasons, that's why I'm happy to be using Firefox again.
The chrome OS is method is pretty cool having a mirrored partitions the one not being used gets updated if there's an error the other one gets booted and reverted