I can't say I follow in the same example as you guys. I practice guitar, soloing, and if I've got some reason to write a tune (ie if I'm thinking about putting a band together or making a demo.. both of which really hasn't happened in a long time) then I'll put some riffs together or go over some old material. It's just a systematic process of piecing together different riffs to create a decently structured tune. Each one has a different FEEL, but they don't necessarily reflect my given mood or an emotion. I don't deal with lyrics at all anymore.

There was a time when I used to write songs about a certain event or what have you, but now it's more of a technical process ABABCAB etc .. this goes here, that goes there, bass'll do this, drum this, melody like this...