Tact is tough when you be three :)

V to abuela: Why are you here?
Abuela: I am your grandma.
V: No, you are not.
Abuela: I am your mother's mother.
V: My mother does not have a mother.

next day i made V call to apologize. After his singsongy b.s. "sorry", my mother asked: "Can we be friends now?" V replied: No!