''Three cheers for Captain Frodo, Lord of the Ring''

Originally Posted by Rumil

Here they are deciding the fate of the free world and Pippin is making light-hearted, if not downright silly, jokes.

Did Gandalf not make light-hearted comments of the gentle treatment given by Sauron to prisoners in the Dark Tower in The White Rider?

To me Gandalf did not want anyone to celebrate anything until the Ring was destroyed and Mordor overthrown permanently. He may have feared Sauron at all times, but in the comfort of Rivendell, where elves freely be merry and sing songs (sometimes overly merry ones), why did Gandalf overreact?