Actually, you can use one of the pranks on Dog for a -50 Approval Penalty and increase it with the bones or Feastday Gift to 100 and actually get a approval bonus from him/her which was previously impossible before the release of Feastday Gifts/Pranks.
XBL GT:SkyKnight618 Currently Playing: Oblivion, FF XIII, Gears of War 2, SO3, Xenosaga Ep 3.
Yeah, Sten's feastday gift has proven useful to me, too. And the approval for dog seems to work with just the gift, even though his approval is already 100% - I gave him the stick and got the stat bonuses all at once.
I use them for max Approval. You can also get unlimited amounts of the Gifts/Pranks with a bug with the Chest in Soldier's Peak, so you could give em all pranks and then gifts to bring it up. Its a novelty thing anyways.