In her second post on 'deadbeats' at Atlantic Monthly for December, Megan Mcardle led me to Google gratitude and enter it into the results in comments:

In Hobbes' Leviathin, gratitude is considered to be the fourth law of nature, following the laws seeking of seeking peace, contracting for peace, and performing one's contracts (that is following the rules of justice). As Hobbes explained the fourth law of nature, "That a man which receiveth Benefit from another of mere Grace, Endeavor that he which giveth it, have no reasonable cause to repent of his good will."
- RE Emmons and ME McCullough

I hate ingratitude more in a man
than lying, vainness, babbling, drunkenness
Or any taint of vice whose strong corruption
Inhabits our frail blood.
- Shakespeare Twelfth Night

'Gratitude is for dogs.' - Stalin

Reply

...Max... (Replying to: Michael) December 16, 2009 3:08 PM
To be precise, "gratitude is a disease of dogs".

Emphasis and choice of translation are mine. Unfortunately 2 minutes of googling did not yield a solid quote to the original [response to Zinov'ev].

It is amazing how normative for our culture Shakespeare is; wise as well. In Totem and Taboo, Freud looked at religion as the reaction to guilt for killing the primal father because he kept the women. But a father naturally loves his children and religion is the repository of our gratitude for our lives in spite of our errors and ingratitude. Shalom.