> A good taxi drive will get you someplace faster than a bad one, will know shortcuts and longcuts, and understands patterns of traffic to avoid them. A plumber

> A good taxi drive will get you someplace faster than a bad one, will know shortcuts and longcuts, and understands patterns of traffic to avoid them. A plumber, on the other hand, typically performs a pretty objective job, short of outright incompetence. I find the opposite is true. There taxi drivers are barely different, but the quality of plumbers varies greatly.