My five year old nephew has inherited my keen observation skills. It must be a recessive trait my brother carried. Last night at the ballgame he said:

“Uncle Johnny, you have a mustache!”

This is the type of thing I will say. I’ll tell someone: “I like your hairstyle.” And I’ll be told, “I’ve had it for 5 years.” I’ll usually respond, “I’ve liked it for all five years, just thought I’d mention it.”

My niece said to her brother: “You just noticed?”

My niece has the family trait of sarcasm.
Whether this is inherited, or a learned survival skill, I am not sure.