That Old Adage is an achievement/trophy in The Missing Link DLC for Deus Ex: Human Revolution. It requires the use of the Social Enhancer cranium augmentation while talking to Garvin Quinn just before leaving the Rifleman Bank Station at the end of the DLC.
No matter what form of manipulation — Alpha, Beta or Omega — you try, they will all fail, but yield the same interesting new insight from Quinn, who is really trying to be honest with Adam Jensen, about his role in the matter.
- The name of the achievement is a reference to a quote by Sigmund Freud, who said of the Irish "This one race of people for whom psychoanalysis is of no use whatsoever." The quote is often misstated as "The Irish are impervious to psychoanalysis," most notably in the Martin Scorsese film The Departed.
- If you are trying to go for the Factory Zero achievement, it will not be attainable in that play through, obviously, because you have to augment. But you can of course save the game just before this conversation, play the game to the end, then load to this point again, augment and talk to Quinn a second time.