Since having sold my T450S (sadly) since I really don't need a laptop that often and have one for work, I popped the drive back in an old Dell Inspiron 1525 from 2008 (hello Core 2 Duo and poor fan control!).
Since this computer isn't that quick, and the battery is very near completely useless, I noticed that the way that Windows is constantly downloading/installing updates and scanning for viruses makes the computer pretty well unusable most of the time. It also eats up my mobile data if I'm on the go and it would seem there's nothing that I can do to stop it.
As a result, that computer is either going back to Windows 7 or going to Linux (likely a derivative of Ubuntu, such as ChaletOS for its sheer beauty).
I'm also holding off on moving from Windows 7 on my gaming rig even though it has the power and bandwidth to deal with Windows 10 endless tasks. This is just more for the principle -- Windows 10 doesn't really seem to anything better for me at the moment. Sure I like the new start menu more, different scaling for different monitors, and the improved snapping/multiple desktops is very nice (more so for a laptop)... but it still just seems like I don't like the direction Microsoft is taking with their forced update scheme, and lack of control over processes.
I'm also not one to get caught up in things like the cloud, social media plugins, etc, at least for now. I know that's where so many services and software suites are heading, but it just seems like now everything wants to be so involved in your computing experience.