The killer for me is a weird combination of Stockholm syndrome and a seemingly drug-like addiction to Windows that I just can't shift. One minute I'll be swearing at the 15th problem of the day that occured on Windows and then spend all Saturday installing a Linux distribution and killing off my Windows Phone and Live accounts.
By Sunday it's got Windows back on it and I'm at it like a raving crack addict again. But I know it's hurting me. I know Linux well and am responsible for a fair chunk of Linux kit but I always end up with it on Windows again.
Last time: unity won't show file copy dialogs suddenly, duplicity backup won't work due to a bug in Ubuntu that has been open for over a year, my FortiClient VPN drops every 5 minutes, I can't find a RDP client (so I can still connect to my day job) that works properly.
Argh just kills me this. I want to do something else for a living now.