Don’t let one persons seeming moodiness or need for solitude ruin the day, especially of you’re spending time in a group of family or friends. They might be being quiet, which can sometimes come across as a bad mood, but they are likely just having a day of contemplation. Carry on with your celebrations and good time. They won’t be offended and they aren’t expecting everyone else to spend the day lost in thought. They likely don’t even notice they’re doing it.