I first saw the quote above maybe seven or eight years ago. It hit me hard then because I knew that was how I operated. Raised to believe I was something to tolerate, when others didn’t meet me halfway or make much of an effort at all, I went out of my way to keep them around anyway. I didn’t question their lack of effort or their lack of respect for my boundaries because I knew I was a lot to tolerate, and this meant I had to work so they would continue putting up with me.
In the years since I first read the quote, though, I have worked to increase my self-esteem. I have at last come to the place where I am able to see my negative qualities without allowing them to convince me I am worthless or worth less. I don’t want to offer a discount on my company anymore. I have a lot to offer my companions. I’m not especially bad, as I previously thought. I’m especially human. And that is awesome because it means I am like everyone else after all. I don’t have to accept less from others in our relationships. I have agency. I can decide what works for me, and I can let other people walk if they aren’t comfortable with what I need to stay in relationship with them.
So now I am at last in the place in the quote. I am finished allowing people to treat me a level below my worth. I am not on clearance. I’m not handing out coupons. This isn’t Goodwill. If what I want is too much, if you don’t want to make the effort, move along. I’ll be better for it.
Live Now and Zen 
Sounds like you have discovered boundaries. I often tell students and clients “People who own it know what they will and will not. Boundaries are important because they set basic guidelines of how you want to be treated. Boundaries telling others to call you when they learn how to respect you..”