I feel like in my 30ish years living in the US, I've been told around a half dozen times that the federal government is on the brink of shutdown and at least twice for my state government. The news always reports really vague and ill-informed-sounding quips about what would happen in a government shutdown. Though I've never heard of any actual consequences that made me or anyone I know notice that a shutdown happened or was looming.
Have there ever been any real, significant government shutdowns in the history of the US? What caused it? What were the consequences?
This isn't an answer to your question, but a very quick clarification: every shutdown has consequences for the "average person" if their employment is in any way related to the government:
The ratings agency estimated that about 400,000 federal employees were furloughed, another 1.2 million federal employees worked but were paid late, and "a couple of hundred thousand private sector employees, many at defense contractors, could not work because of the shutdown and are unlikely to receive back pay."
https://www.cnbc.com/2017/04/18/government-shutdown-heres-who-keeps-working-and-who-doesnt.html
and, e.g. national parks being closed certainly has an impact on anyone intending to visit one. But I will leave it to others to provide some actual historical examples, if relevant ones exist.