George's last name is Costanza, so he must be Italian.
Being Jewish and originally from New York, I can attest to the fact that there are a host of similarities between the Italians and Jews in New York City.
Now I'm the first one to get my nose out of joint when I hear generalizations about ethnic groups, but very many of my acquaintances in NY were either Jewish (all my family) or Italian, and, for many of those whose families had been in America for less than 3 generations, alot of the following holds true:
Both groups are from recent immigrant roots, both just want the very best for their kids and would sacrifice everything for them, and both believe that there is much value to the extended family...so much so, that it is not unheard of to have 3 generations living under the same roof.
I now live in England, and have come to love Seinfeld because it shows the ethnic quirks every so often. Trouble is that the BBC broadcasts the show very erratically and often several seasons late. Either way, the show keeps me in touch with the City, and, although I can't stand Seinfeld the comedian, I would kill to see Seinfeld the show five nights a week!