When you look at some of the pull outs that cars do on other cars they are fractions of a second away from each other, but there's never a word or gesture. As much as i hate to saay it i reckon most drivers (except me) are pretty good at judging distances and gaps.
As cyclists i think we react because we are vulnerable, but there's not always a real danger there.
As a car / mini bus driver myself, yes cars do manage to get around leaving quite tight gaps between them, especially on Coventry's ring road!
however, a car does not wobble, it does not need to swerve to avoid a pot hole (although for the mechanical longevity of your car it can be a good idea to avoid them) and if you do get the distances wrong then it's a small nudge and a new head / tail light
not so if you miss-judge the distance between a car and a cyclist, it is not possible, in a nudge, to end up just bumping the other vehicle slightly until you've both stopped, however to do so to a cyclist could have the rider under the vehicle.
as such, cyclists need to be given more space when maneuvering around them - as all of us on here know.