Classical guitar. When I got an electric guitar to jam with friends I soon realized that I had no sense of melodic soloing at all. I only understood rhythm playing but my fingers were clumsy and hit too many dead strings with the closer string spacing of an electric. Figured since I understood rhythm better and the bass strings were further apart, I'd be able to play the bass better. Worked out well because I was the only bass player in the local music scene in a sea of guitarists so always had a band to fill in with.