When I was studying at MIT people would knock on my door all the time to borrow tools, cables, kitchen gadgets, and various other things that I typically had. I didn't mind at all. I think we need to reduce the amount of "stuff" in the world and share more.

Since I graduated and in the Bay Area now I realized that my closest friends, and pretty much anyone I knew, is no longer located next to me. Every time I want to borrow something it involves figuring out when someone living 20km away from me will be available, worry about bothering their schedule and making them stay home when they don't want to be, and then spending $25 on Uber rides* round trip to get it, and then another $25 on Uber rides to return it to them later. In most cases I could just buy that drill off Amazon for less than $50 instead.

*I don't own a car because I avoid using a car when not necessary (e.g. commuting with a bicycle and public transportation), only need a car for occasional hiking trips and events, and believe in sharing, and my Lyft+Uber+Zipcar+Enterprise costs per month are less than the cost of car ownership.