It's the leverage the socket and ratchet give you along with the tapping that seems to loosen things up. Or maybe someone sprayed some of that Kroil (the oil that creeps) on it and you didn't know it! Either way, glad my advice helped. I'll give you my brother's name here so you can tell him it my advice actually works now and then.
My typical conversation with him goes "Hey Nick.. how would you....?", I reply and he does everything other than what I suggest.