The Art of Mixed Tapes/CDs

Wherein lies the art of this popular hobby? Are you the type who makes mixes without regard for an overall theme, based more on choosing songs you like; or are you the type who first contemplates with great care a theme or framework for your aural construct?

For me, the art of mixes lies in the overall mood or feeling I'm aiming for, with lots of thought put into finding songs that compliment or contrast other songs on the mix.

I like to pick up on a melody or beat that was in a song and carry it over into the next - for instance maybe a song has a similar guitar line line with the one previous, but is still very different in overall style.

Also, I like building sub-themes, so I might have "Turning Japanese" followed by a Shonen Knife tune. Sort of my little game with sequencing.

What do you do? Do you think it is important, or does this kind of obsessive anal retentive intellectualism bore you?