I've fallen in love with Windows again. It just works. Power management rocks, battery life is good (8 hours on my 2007 Lenovo T61!), the hardware is damn cheap, the licenses cost me virtually nothing, literally everything I plug into it works, the tooling is pretty damn good, utils I wrote for Windows NT4 literally 14 years ago still just work flawlessly. My Linux machine is just a VirtualBox VM.
Yesterday I bought my second Windows Phone (Lumia 820). This also just works. Email is the same everywhere, all the apps just works, plays any mp3 without complaining (my sodding iPhone never did!), Nokia Drive just works, maps actually work (again something my iPhone shot down), talks to exchange without problems, is exactly the same as my old Windows Phone 7.8 device (no who moved my cheese), opens all my documents nicely, reads any pdf fine.
Seriously, it's just all boringly functional and uneventful these days.
Bear in mind I am coming from a background on hardcore UNIX machines (big Solaris, HP-UX machines), through FreeBSD to Linux to OS-X.
The worst pain I had was with Solaris (on Tadpole SPARCbook) and just about everything Apple, particularly their unreliable hardware (4 Macs returned for repair!), app compatibility problems, piss poor battery life on iPhone 3/4, shit crock of a POSIX environment and shoddy attempt at online services.