Awful Apple Server OS If you were wondering about using an Apple Xserve or anything running MacOS X at the centre of your infrastructure, I would strongly advise against that idea.
Apple make good desktop and phone operating systems but are awful at servers IMHO.
Phone stuff - connection settings and what works with Mac and GNU/Linux etc.
Broken Windows - Once Microsoft Windows has been infected, it is often impossible to repair because the botnet controllers change the operating system with a rootkit to hide the infection.
Nearly all the annoying spam emails you receive are sent by unknowingly infected Microsoft Windows computers so be sure to thank Microsoft for your wasted time.
Not evil - I know we are not supposed to say that microsoft are evil,
but when they try and prevent people from having free and open access to documents that they wrote themselves, it certainly doesn't look like they put the paying customer first.