Corroborating some of Noah Millman's points from earlier, Gwen Sharp summarizes Suzanne Mettler's research (pdf) on the self-awareness of government program beneficiaries:
Mettler argues that recipients are less likely to recognize themselves as benefiting from programs that are part of what she calls the “submerged state” — programs and policies that provide incentives and motivations for particular behaviors in the private sector, rather than overtly directing behavior. If you receive food stamps, you interact directly with a government agency…. On the other hand, if you participate in the government’s mortgage interest deduction program, which encourages home ownership by allowing people to deduct the cost of mortgage interest from their taxable income (which you can’t do with rent costs, for instance), it’s less noticeable that you are benefiting from a federal policy.
In addition:
[T]he programs recipients seem least likely to recognize as a government program are among those the middle (and higher) classes are most likely to use, while those more common among the poor are more clearly recognizable to those using them as government programs.
The Dish 