Congress did not act, so we are facing a federal government shutdown. The shutdown will close national parks (like Acadia in the fall) and museums and furlough hundreds of thousands of federal workers. BUT there are a number of government services that will see business as usual. Many are "essential" and others are funded through money not in the budget that Congress is fighting over. 

Here are some of the things you likely don't have to worry about: Social Security and Medicare, The passport office is self-supporting so it’s safe, but passport offices located in federal buildings affected by the shutdown may not be able to open. Air traffic control is considered "essential", so planes should still be able to take off. Mail delivery is set and the federal courts will keep operating for now.

If this is a short shutdown the impact on the average person will be minimal, but if the shutdown continues for an extended time it could start to affect more in the way of social services and that starts to affect the poor and important things like federally funded flu shot programs that would not be carried out. And while federal subsidies for education would continue to be disbursed, payments for low-income housing vouchers, heating oil assistance and food supplements could be at risk.