It's going to take a lot of patience to deal with a friend who seems hell-bent on spoiling your fun today. Whether they're miserly, irritable, or just plain grumpy, you don't have to encourage it. Try to put some distance between you and this person. If that isn't possible, politely tune them out. But don't expect them to put an end to their negative energy or complaining. Just beware that you'll probably have to endure it for a while.