Think Progress is accusing Ron Paul of hypocrisy for criticizing social security but taking it (they also suggest that he compared social security to slavery, which he did and didn't: He did in the "immoral" sense, but not in the "social security is a type of slavery sense):
Paul is, of course, not the only conservative to benefit from government programs that he or she opposes. But his crankish view of the Constitution has brought him to the conclusion that Social Security is altogether unconstitutional, which also hasn’t stopped him from collecting benefits.
Any critic A's criticism of policy x naturally leads critic B of critic A to see whether A is consistent with regard to x. Since x is government policy, or law, it's very easy to spot alleged inconsistencies. I'm against, at least I think I am, various tax breaks for people who make over a certain amount of money. These tax breaks might benefit me. I'm not a hypocrite for not writing a check to the federal reserve. I'm a hypocrite if the policy I advocate goes into effect, and I do not abide by it.
People might remember that this is, in essence, the Buffett criticism (we talked about it here and here and here and here): if you like taxes so much, pay voluntarily. Such criticism was bad then, and it's bad now.
It's bad in part because it would make it practically very difficult to criticize laws and policies without engaging in civil disobedience of one form or another.