GADIY stands for "Go And Do It Yourself". Anothersimple phrase to tell someone to do their own things by themselves.
john: hey, can you help me get some juice from the fridge?
mary: What?? I'm busy here! G.a.d.i.y.!
john: what's that?
mary: It says, GO AND DO IT YOURSELF!
short for " i don't give a fuck" which is a very contagious disease causing massive amounts of random anger induced outbursts, spontaneous lack of interest in just about everything, increased will to start and or instigate fights with no clear motive. WARNING: MASSIVE AMOUNTS OF BOREDOM WILL TRIGGER THE I.D.G.A.F
Terry:what the hell is Jason's problem, he just cursed out the teacher and slapped his own girl in the mouth.
Brian: He just caught the "I.D.G.A.F syndrome" man!, watch out before he does some more random shit!!