There's a quote from P.J. O'Rourke that illustrates the point well:
The Democrats are the party that says government will make you smarter, taller, richer, and remove the crabgrass on your lawn. The Republicans are the party that says government doesn't work and then they get elected and prove it.
A central tenant of the Democratic Party is that government can be a force for good and should be run well. Republicans try to tear the government down, especially at the federal level. The party as a whole doesn't care nearly as much about good governance principles, though there are of course exceptions.