How much do you know about your car's internal combustion engine and components?

Your home electrical?

Your home plumbing? Natural Gas? Lawn care?

The pumps that fuel your car tank?

Not everyone can be an expert in everything. Someone who makes their living perfecting one of those aspects might look at things you do and say "don't do that, you're damaging it" but to you its "who cares? I just need it to work and its been fine up until now!"

Computers/software might be your thing but they're not Grandma's so don't push your agenda on someone just because they might have some ignorance you don't.

Yeah, exactly. We almost live in computers, most of our friends and colleagues do, but there are so many people for who computer is just a black box. And there is nothing to be angry about. You don't want car mechanic, or plumber to be thinking that you are an idiot, casual users don't want that either, they just have more important things to care about :)

Indeed. I used to catch tons of shit about not understanding cars from a mechanic friend until his laptop died and I helped him recover photos of his kids.

Now we're both content to be wizards of our own domains without talking down to each other about it.

I would have expected a lot of HN users and a majority of those working professionally in technology to have at least basic high school knowledge of electrical and mechanical principals.

If I where interviewing some one for a developer role and they had not at least heard of ohms law or similar basic principals I would probably pass on them.