The Reddit meme Good Guy Greg is a one-note joke: It's a photo of a man smoking a joint, with words demonstrating why he's a good guy published on top and below the man's face. Examples include "Doesn't drink/Doesn't lecture others on why they shouldn't drink" and "Knows you forgot his name/Tells a story where someone says 'Listen, Greg.'" The female version of Good Guy Greg is Good Girl Gina. The things that Good Girl Gina likes to do are pretty different from Good Guy Greg: "Boyfriend works 2 jobs/Waits until 10pm to make dinner so it's still fresh," "Notices you checking her out/smiles and takes it as flattery," "Is a vegan/cooks you a mean Thanksgiving turkey," and "Gives you a blowjob/doesn't expect you to go down on her."
So what can we glean from all this? If someone wants to be a Good Girl, then reddit already has it figured out. A Good Girl is an object to be lusted after. A Good Girl makes sure you're sexually satisfied, either by her or someone else. A Good Girl defies stereotypes, unless they play into your desires, like when she cooks for you. A Good Girl plays your video games and watches your movies, and she'll bring you food and drinks and drugs, but a Good Girl won't talk about any of those things, because she is a Good Girl. And a Good Girl keeps quiet and doesn't rock the boat.