Differential Diagnostics in our Field

So as I'm watching the series "House"....as I have been told I am a lot like him....but in the automotive world. I retort with "I think I invented that!"....he didn't.

Onto this "Differential Diagnosis" thing. Every time I read a POST on my Technical Support Site: www.euro-diagnostics.com

I see this "Differential Diagnosis" thing happen. You know that we all are "Doctor's of the Wrench", as we Diagnose a sick car and then if we are good enough, we fix it.

As doctors of the human machine, they bury their mistakes....we marry ours.
One doctor washes his hands before he goes to the bathroom....the other washes them after....we hope.
One doctor's machines ONLY has 2 models, and haven't changed in 75,000 years....and all of the components are in the same place. NO changes!
The other doctors machines change ever 6 months, and all of the parts shuffle all over the F*****G place.

So why are we considered "NON Professionals"?? Or are we??

Would really like some feedback on this.....Do you have the answers??

As the Beatle song goes: "Turn Me On Deadman".