Sarek and Kirk don't get along. Either TOS movie era or Reboot would probably work. Sarek gets a thrill from getting a discount or a bargain. He likes to brag about how clever he is at investing, but somehow despite all his credits when he goes out with family he manages to stick someone else--Kirk--with the bill. He holds a grudge for not being present at his son's bonding ceremony--but he wanted Spock to pay for his freighter tickets. You get the picture.