My favorite Jewish joke, from Rabbi Telushkin's book Jewish Humor:
In the late 1930s, a Jew is traveling on the subway reading a Yiddish newspaper, The Forward. Suddenly, to his shock, he spots a friend of his sitting just opposite him, reading the local New York Nazi newspaper. He glares at his friend in anger: "How can you read that Nazi rag?"
Unabashed, the friend looks up at him. "So what are you reading, The Forward? And what do you read there? In America, there is a depression going on, and the Jews are assimilating. In Palestine, the Arabs are rioting and killing Jews. In Germany, they’ve taken away all our rights. You sit there, and read all about it, and get more and more depressed. I read the Nazi newspaper. We own all the banks. We control all the governments."
I think of this joke every Sukkot, because sometimes it seems that Nazis are the only people to whom I would not have to plead the case of my Jewishness. It never stops surprising me how eager people are to tell me that I'm not a real Jew. Not in a mean way, either: just as a fact, the way you say that the man-o-war jellyfish is really four organisms or that the dent between the nose and lip is called the philtrum. Jews do it, gentiles do it, strangers do it -- and it's not obscenely hurtful, but it does hurt. The question isn't actually so cut-and-dried, and I've been thinking about it for my whole life. Because I'm not sure what I am. You seem positive what I am, but that's because you don't know me!
The other side of the problem is that I don't want to appear disrespectful of my mother because I don't identify with Protestantism, in which she was brought up. It would be too strong to say that I "rejected" it because it wasn't really presented to me as a thing to be accepted or rejected. Judaism barely was either, for that matter. (We had seders and lit the menorah, though.) Neither of my parents is outwardly religious: my father eats matzo on Passover, I think mostly because he likes the way it tastes with peanut butter, and my mother likes to see me on Christmas day, and that's really it, as far as I can tell. So the weird thing is that I have a sense of myself as belonging to any religion. To the extent that I do.
I describe my religious heritage to people like this: "My mother is a lapsed Protestant and my father is a lapsed Jew, so I grew up half Protestant and half Jewish, but all lapsed."