[globular-toast]

I was trying to think of other technologies people use but don't know it. If people drive they probably also know that they use the road, but maybe they don't know that they "use" the drainage works that were put in hundreds of years ago. At what point does it become silly to ask the question? "Do you use the water treatment facility on the edge of town?" "Do you use money?"

[fragmede]

Banking. (Which is a technology, albiet quite an old one.) If someone doesn't personally have a mortgage or car loan, and gets paid in cash, and doesn't use banks at all; Does such a person need banks to exist? Does society? Some people I've talked to honestly believe the answer is no.

[SkittyDog]

To be clear, are YOU advocating for the belief that banks don't need to exist?

Because the statement is technically true, but basically meaningless... Cars don't need to exist, modern medicine doesn't need to exist, electric lightbulbs don't need to exist. But they all provide conveniences and functionality that most people seem to appreciate, and would not be willing to part with.

[fragmede]

Water's a really good one! Where does your tap water come from? What water district are you in? Or conversely, what's your ISP's ISP (Level3/etc)? Where's your closest Internet Exchange (IX)? How many hops away are your closest friends on the Internet?