As well as giving me a reliable* platform to work on, this had the enormous benefit of allowing me to say "I don't know anything about Windows any more, so if you want me to help you with your computer you'll have to switch to Linux" to friends and family. Many switched, and I must have saved myself months of fixing Windows machines.
So I offer a heart-felt thanks to Linus, GNU and the Debian and Ubuntu maintainers every day.
* Last week my xorg.conf disappeared. After half an hour cursing while I found and fixed the problem, I realised I couldn't remember the last time computer problems had impacted my productivity - it has certainly been several years. I obviously have no idea how Windows runs now, but my recollection is that it wasted several hours a month.