I've been using WindowMaker for 10 years. It's pretty perfect. No gimmicks. No unnecessary features. Lots of flexibility. Minimal. User friendly. Fast. Stable. It just works.
If someone has used Windows 95 before, a whole slew of operating systems after will be intuitive and a random user will know how to use it without instruction. They don't need anything more advanced. They just need it not to crash or bloat or change and become confusing. Most people just want shit to work.