Because I said so!
OK, that is kind of a lame reason, it never worked when my parents tried it on me ... how about this one:

When Leo Fender, father of the electric bass, left his namesake company, he still wanted to be involved in the evolution of the electric guitar. In 1971, former Fender Vice-President and General Manager Forrest White and former Fender Sales Manager Tommy Walker (both of whom had left the CBS owned company by that point) were looking to start a new company, one based on the idea of making "vintage" sounding and quality amps and equipment. Leo Fender became the venture's financial backer and a silent partner in the new company—Music Man. Soon they realized that they needed a hot selling guitar and bass to fill out the line, and together with Leo's CLF Research, they set out to make even better instruments than the "Big F" had produced. The StingRay Bass was a stunning design tour-de-force. Look at this picture and tell me you don't agree (and I'll tell you that you're nuts)!

We'll find out more about Mr. Forrest White on subsequent pages, but suffice it to say that the shape you are looking at on the right is his brainchild.

Thanks Forrest, wherever you are!