You even see it on HN. Someone will come along and talk about how a senior dev at Google can expect $250k a year. You'll get two categories of replies: "I don't believe this at all, Glassdoor proves you are wrong, nobody I know makes that, blah blah" and "bro that is totally normal". $250k is honestly on the average-lowish end for a senior eng at a major SV company in 2017. Much of the industry is not only unaware of reality but refuses to believe in it. This includes real engineers who do real work at real companies and comment actively on Hacker News. $250k for a senior engineer is just completely outside their reality.
On my last job search, my best job offer was about 2x as high as the worst one. The guy who made the worst one--which was about 30-40% below my minimum stated range, depending on how you valued the equity, so he had been stringing me along, but anyway--he started arguing with me about my unrealistic expectations, and wouldn't stop talking until I told him I was going to hang up if he kept trying to talk me down.
I know it's considered bad negotiation, but if I can't figure out the salary range of a job opening, I'll name my requirements up front. Over 50% of the time the conversation ends there. I know at least twice people assumed I was over-highballing as part of some misguided negotiating tactic when I actually was a little conservative.