You can do better. It started one night when we realized that we were both pining over the respective guys that we were seeing (or maybe more accurately, trying to see) and evaluating our own behavior towards them, asking what we could have, should have, would have done differently.
Then we realized that we could have, should have, would have done nothing. If the way these men were treating us was making us unhappy, then why should we be questioning ourselves? And "You can do better" was born.
We realized that if someone's behavior is a source of unhappiness or discontent, then not only would we be unable to change the person to make us happier, but it wouldn't even be worth the effort! So we made a list of everything that made us unhappy, everything that we should not allow ourselves to settle for, and said that if someone we were seeing belonged on the list, then we could do better. Sometimes it's funny, sometimes it's heartbreaking, but it's always true. And once it was written down, it was like a big dose of reality and empowerment rolled into one.
The purpose of "You can do better" is not to set impossible standards or refuse to compromise. "You can do better" is about not compromising respect and fulfillment. It doesn't matter if he's into you or not, but if he can't pull it together for you, then you can do better!
If you can't tell if he's hitting on you or trying to hire you, then you can do better!
If he tells you you're "pretty, but could be beautiful...with makeup," then you can do better!
If your car broke down and, rather than wait one day for you to arrive, he slept with someone else before you got to town, then you can do better!
If he spends a month rafting the grand canyon and after he gets off the river he texts you how much he misses you and wishes you had been there but then sleeps with his ex the night before you are supposed to meet up, then you can do better!
If he's all enthusiasm and no details, then you can do better!