Talking to Chuck and asking for his advice leads to him doing a Tarot reading for the Vault Dweller. By getting various "fortunes", Chuck will place markers on the world map for the locations.
He will give the Vault Dweller between one and three readings for locations: the Brotherhood (if the Vault Dweller never had anyone mark it), the military base (if the Vault Dweller has not been there or found its location in the Cathedral vault), and finally the Cathedral (always).
Next time afterwards he will draw the fool card and the Vault Dweller's Luck will go up permanently by 1.
Mocking Chuck's fortune-telling will offend him and result in his refusal to read the Vault Dweller's tarot.
It is possible to get an extra Luck point when talking to Chuck the first time, then asking for advice. This only works as long as Chuck is not asked about his job until after receiving the Luck bonus.