I got a pack with a couple of games. I accepted the pack, but one of the games I don't want to play, and I never have. Does it work to give only that game back? If it helps; the game is Need for speed Shift 2
This is a bit of a trick question. The answer is simply: No.
What restrictions are there on trading Steam Gifts?
Trading a Steam Gift is very similar to sending a gift to someone; just that once it is traded that user can then either trade it again, or open it for themselves. There are no restrictions on territory.
A bundle of games or a pack is considered as one game. Unfortunately, you will not be allowed to trade that game or gift it under any circumstances.