What are the best systems that focus on social interaction?

[GentlemanVoodoo]

Hmm...one of the more interesting mechanics for social interactions I like was in Legend of the 5 Rings 5th Edition. The different rings along with the Shuji abilities made conversations an interesting and deadly affair. Not familiar with prior editions but I assume this is them as well. Though I didn't care for Vampire the Masqurade 5th edition, I did like the idea of social interactions wreching carnage to one's Willpower which for this game has been a very crucial stat for characters.

Anything else tends to fall to the rules light games like Fate where social interaction is more pronounced than the nitty gritty of mechanics.