'Willson' is an enhanced version of 'Wilson', because of the second L. Where as a 'Wilson' is a straight up G, a 'Willson' is a straight up GH. Which is a whole letter more than a G.
James: Dude, that guy is such a Wilson!
Dave: No way, he's more than that!
James: You mean like a WilLson?
A name to yell at someone leaving you