I relish the challenge of playing complex lines and getting them down is an achievement. At the moment i have decided to 'try' to learn The duel of the tryant and the jester from Return to forever's album RomanticWarrior. The album is filled with simple and effective and full bore complexity bass lines.
I also do reggae which, though mostly uncomplicated, is a great exercise in consistency, restraint an holding down a groove. Something i really enjoy.
So i guess i love both.