English Slang Collection：
good luck with that
[釋] statement used to express doubt in the future success of sb's plan;
[例]A: You know, Jane's gonna play baseball. B: Well, good luck with that.;
Good on you
[釋] congratulations;
[例] A: I got my offer from UCLA. B: Good on you.
good looking out
[釋] the act of watching out for someone in his best interest;
[例] A: I took notes for you when you were out. B: Thanks bro. Good looking out!;
good samaritan
[釋] a person who helps others;
[例] Thanks a lot. You're a good samaritan.
good egg
[釋] a good person;
[例] Thanks for buying me lunch; you are a good egg.;
good one
[釋] something well done;
[例] A: I passed all my finals. B: Wow... good one.;
good sport
[釋] easy-going, agreeable;
[例] Come on, be a good sport and help me.