Some people just have no boundaries and should be stopped. For sure the OP's neighbor is one of them.
But I find it kind of sad also when people say they have lived somewhere for a long time and no one ever borrows or lends in their neighborhood. It is admirable to not take advantage of the neighbors or let yourself be taken advantage of.....but I think people should work together and support each other to make life easier. Wish I was perfect, but sometimes I am in the middle of cooking something and realize we are out of an ingredient. Why in the world should I have to stop and run to the store for an egg? That takes time and gas. I would hope that my neighbors would come to me in that case and I would be happy to help out. And I hope they would be happy to help me, too. But after reading this thread, I am afraid to go to my neighbors for a quick assist....afraid they will be put out by my humble request and think poorly of me.
For the last 12 years we lived next door to a family with 4 kids. We have 2. The kids played together and the adults became good friends. As the years passed we borrowed back and forth just about anything you could imagine. Their grill broke, came over to our deck to use ours. Since our kids swam in their pool, our hose helped fill it. Big party? Our deck furniture went over the fence. Their kids need a ride? Come ask Miss Lisa. i need a ride to pick up my car from the repair shop? Yup, neighbor to the rescue. Now, there were times I started to feel taken advantage of as I am a stock-up shopped and neighbor was always out of things, hence I usually couldn't get what I needed. And when the kids started to come on their own to borrow things like sugar because they wanted Kool-aid too often, I did learn to be "out". But I loved the security of having an extended household next door....and I loved the closeness. They just moved a couple of months ago and I miss them tons. Well, all except the dogs going in my yard