Mac Server Room
I have had the unfortunate job years ago to work in a Mac server room! We had to get it all ported to Windows, Exchange etc (yes the mail server ran on a Mac too!). As I had limited experience on Macs I had to replicate their environment back in our office to plan the port of their systems & mail...
Never seen a place like that since and hope I never do!
For all the Linux/MySQL fanboys, once you get into a corporate environment the support contracts, training etc required to provide proper support & maintenance of these 'free' products is shocking! The same can apply to freeware/shareware - tucked in their license agreement is a 'corporates not allowed to use' clause... big fees! Even Adobe Reader has this tucked away, corporates roll without an agreement at your peril.