Credibility = Talent x Years of experience + Proven hardcore accomplishment
A productivity article I read mentioned that “multi-tasking” — though it just amounts to frequent task switching — is an invisible productivity robber, and a number of people took issue with that. Touting their success with multi-tasking and using generalizations that amount to: “everyone’s different, so this isn’t true.”
The latter is an empty argument and doesn’t convince me. If I say that the sky looks blue because of its wavelength and how that interacts with the atmosphere, is someone going to say “everyone’s different, so that may not be true?”
But it got me to thinking more about how so many people thrive on a self perception of absolute uniqueness, which I think is also a masquerade of superiority. If everyone were so different, we’d know nothing about people in general and how they behave. There’d be no foundation for our expectations and actions. And by using one’s uniqueness to brush off advice or criticism, it’s a replacement for introspection. The superior do not critically reflect on themselves.
Tech Is Hard 
There’s also pretty solid research showing how multitasking actuall makes one LESS productive.
I think they call it context switching, and there’s overhead incurred. How can rotating between a few tasks and coming back to the first be any less disruptive than having someone interrupt what you’re doing, right?