How do your characters celebrate? Feasts etc are expected (!) - see the celebration of Bilbo’s 111th birthday in The Lord of the Rings to name one example. So what makes up your feasts in terms of food and drink? Who does the preparation?
Are holidays linked to religious festivals or deliberately kept separate? Equally is there a mixture of religious and secular events?
If a holiday is a traditional one that everyone takes part in, would there be any grounds for characters to object to joining in? For example they are not from the religion the holiday is based on so don’t feel they should take part. Is that attitude tolerated or is it a case of “you will celebrate whether you want to or not”?
Are the holidays a genuine time of relaxation or used to keep people under control?