a) neither they or anyone in their family has red hair
b) they have a last name like Richards, Bukowski or Weisburg
c) their skin doesn't explode when exposed to direct sunlight
d) they can't hold their booze
e) the latest relative of theirs that actually came over on a boat from Ireland died 97 years ago at age 53
Mike: I'll go as long as O'McFinniganly doesn't walk around wrapped in the Irish flag, fake an Irish accent, and throw up and pass out all shitfaced in the middle of the street after the third bar.
Zack: You know that's exactly what'll happen.
Mike: Let's take pictures this time.