It’s good when nice things happen. With the way the Doctor’s life goes, nice things are something to be grabbed onto when they happen. Because in five more minutes you could be running for your life from some terrible creature intent on destroying the universe, and you right along with it since you happen to be in the way.
No doubt there’ll be more running later, but now’s the time to make merry, to celebrate the Ponds’ big day. He couldn’t be there for the wedding, but he’ll make the most of the party food and dancing.
Dancing is good!