@b0rk in '94 I used (sun's) db and a friend asked me why I didn't use gdb. It was such an amazingly different experience, the gdb ui seemed to be designed with care---dare I say love?---for an actual human (me!) using it.
I went to read all of gnu.org, the philosophy (empowering the user instead of keeping them ignorant), the coding standards (info instead of elitist manual pages, no arbitrary limits, etc ...) and decided I wanted to be part of this.
The reason some of us prefer to say GNU/Linux is rooted in the idea that even people that have been using "Linux" for decades, may not have heard about GNU.