I use both Windows and Mac OS X every day, so have become accustomed to how Windows must restart after updates.
To my surprise the latest Mac OS X release of Mountain Lion numbered as 10.8.1 also required a restart:
It’s annoying to me when I have to loose several minutes of productive work time during the business day to install an update and wait for a restart Oh well, during the restart I just went over and used my iPad instead where I can continue to read all of my email accounts.
The official list of fixes for 10.8.1 include:
Resolve an issue that may cause Migration Assistant to unexpectedly quit
Improve compatibility when connecting to a Microsoft Exchange server in Mail
Address an issue playing audio through a Thunderbolt display
Resolve an issue that could prevent iMessages from being sent
Address an issue that could cause the system to become unresponsive when using Pinyin input
Resolve an issue when connecting to SMB servers with long names
Address a issue that may prevent Safari from launching when using a Proxy Automatic Configuration (PAC) file
Improve 802.1X authentication with Active Directory credentials