I think the more annoying ones are the one who think because you're half, you encompass all the stereotypes of the dominant culture (I'm half Mexican, so I must love beans and spicy food, speak fluent Spanish and have a Chihuahua along with some husband with roach killers spitting out his babies in a clean house and watch telenovelas when I can. Pretty much none of that is true. for what it's worth, my dad is white).
It got worse when I had my daughter, who looks just like her white dad (light brown hair, blue eyes, pale skin), and people being like 'I don't understand. why doesn't she look like you? she should have dark hair, eyes and skin' and all I can say is 'I don't know. we're shocked also.'
but now that I've had people say they thought that maybe I was Italian or Mediterranean, I've decided now to let people think that. Works out great because my girl loves Italian food (forget pickles and ice cream. I wanted pasta and garlic bread when I was pregnant, and she still wants those foods) and has an Italian name (I named her after an Italian guy. Her last name is German).