Grr to you day!
A phrase used to insult someone, without actually hurting their feelings, because they'll be so confused by it.
Person a: (wins a race) Yeah, I won! You suck!
Person b: Grr to you day!
Person a: huh?
person b: (smiles)
Person b: Grr to you day!
Person a: huh?
person b: (smiles)