My desire to befriend some crows is only increased by this comment.
Hooded crows seem to be friendlier, and come the closest, but rooks open their mouths as if I am their parent. They pick up cat food in the air and, sometimes, from my hand (some of the hooded crows do that, and pretty much all the starlings, which we call "honorary crows"). Jackdaws are the least friendly (or the most scared). Sometimes they come in couples, sometimes with their kids.
There are no ravens in my neighborhood, which I find sad. If I ever befriend a couple of them, I'll call them Edgar and Lenore.