Why “upstart crow”? What is an upstart crow, anyway?

The best books start here.

To begin with, it is an insult slung at the young Shakespeare in 1592 by older, more-established, but less successful playwright Robert Greene. His obvious irritation at the younger artist’s pluck and nerve is, we think, typical of the response of the old guard toward any new talent. There is something in the phrase that speaks of courage and brio and daring, and we feel we should all be upstart crows when it comes to our writing and our work.