It is not in your best interest to interrupt the gravy train. While I have no idea where that expression came from, I do have a lot of examples of why this is a bad idea. For starters, you will lose your supply of baked goods. I bake a lot. In fact, more than most people I know, and I will often share my plethora of baked goods with others. When someone says "Thank you. I love homemade bread," I appreciate it. When they are happy to get homemade from scratch brownies or cookies, I'm happy too. But when they say something like "oh, I don't eat flour any more" or "thanks but I'm on a diet" or "I don't like that anymore" it ticks me off. And when I'm ticked off, the baked goods stop coming. And when the diet inevitably ends, as they always do, no baked goods are coming anymore.
The same with movie and party invites. I understand that everyone can't go to everything. And I understand that things come up. But when you say you're coming and don't, and when I bought your movie ticket because you said you were coming and then you didn't, guess who isn't getting invited to the movies anymore. And guess who isn't invited to parties anymore?
And guess who is at the bottom of my list. And if you are at the bottom of my list, I am not going to go out of my way to help you. If you have a problem, you're going to have to deal with it on your own, because I'm done with you. The gravy train is no longer stopping at your stop. And it's your own fault.