1) Protecting the Nation against Financial Bankruptcy: Gov't financial policies that prevent Financial Depressions and stimulate the economy. Where do people look when the economy is tanking or there is widespread fraud?....THe Feds.
2) Public Health Programs: The CDC and NIH have literally saved the lives of the nation through innoculation programs, health research, establishing health care provider protocols to protect health care workers in hospitals, and nutrition. Also, standards for doctors and nurses and medical technologies.
3) Social Security: Support for the Elderly, for families that lose their primary caregivers, and for the disabled have been wildly successful programs. While it needs to be adjusted along the way, it is one of the most successful Federal programs ever.
4) The Interstate Highway System: Funding and establishing standards and improving highway technologies have made our highways hugely successful.
5) Consumer Protection: The FDA has done an outstanding job of testing pharmaceuticals, and establishing standards for food handling and distribution and testing. Requirements for seat belts and air bags and other safety enhancements have saved millions of lives.
There are many more, but these are the ones I would say are the top 5. And, that doesn't even include the successful military programs.
Are there problems with the above programs?...Sure, but the problems are minor compared to the major achievements and the big picture. Whenever you have a big enterprise, there are going to be problems...every company in American has them, too.
It's important to separate the POLITICAL differences we have over these programs from whether the gov't is successful at operating them. Very often partisans like to claim a particular program is horrible and exaggerate their problems because they have a political difference over whether the program should exist. If you don't agree with a particular program, that is perfectly fine, but don't trash the gov't program just because you disagree with it philosophically.
Cody