The term government shutdown, as you're doubtlessly aware, is inaccurate in the first place.
The federal government doesn't actually shutdown. Instead it prioritizes.
During a partial federal government shutdown there's actually a great deal of discretion with regard to what stays open and what doesn't. Let's start with just the facts...
The reason "shutdowns" are largely a modern phenomenon isn't due to increased partisanship - it's a byproduct of the budget process created 1976
Since 1976 there have been 19 "partial government shutdowns"
Eight have reached the current stage where certain agencies and their employees are furloughed (most recently in October of 2013)
The government doesn't work on pay-go, or a revenue in, revenue out approach - we're still accumulating debt and that's because...
The Office of Management and Budget (currently led by Mick Mulvaney) determines what remains open and what doesn't
The average impact is that only about 20%, or 1 in 5 of the 430 federal agencies is impacted (during the 2013 shutdown only 17% of federal agencies were impacted)
So, let's boil this down to brass tax for a minute. First, Congress created this process for themselves in the 70's (as a way to increase partisan leverage). Second, we've averaged some type of partial government shutdown every 2.2 years since. We've averaged this type of shutdown every 5.1 years. The only reason it likely seems like a rarer occurrence is little more than media manipulation.
With the OMB largely making the priority determinations about what stays open and what doesn't - you get a sense of what the priorities are of the current administration which can actually be insightful if you view the process analytically. And by the way, if 344ish federal government agencies are still "working" during a shutdown generally - we still have way too freaking much federal government.
I'll say again. Take a pen and a piece of paper and see how many you can actually name. So, if an agency you don't know exists but that you pay for isn't operating...Ya get the idea. It's the forest & tree thing going on for the most part (except that the media is loud and obnoxious trying to find that former tree in the forest).