This is only my take, but Symbian always felt as if I was doing what it wanted me to do, not a workflow that was intuitive to what I wanted to do in a few instances.

It was somewhat inconsistent and at times, bothersome or controls were not immediately offered. Same for Blackberry OS, imho. I've never been a fan of either, but that's just my personal opinion. I felt the same way for iOS too, if you want to pull that out.