Researchers of the HSE Graduate School of Business trained a machine-learning (ML) model to infer users’ subjective wellbeing from social media posts. Having processed 10 million tweets, the researchers compiled a rating of holidays celebrated in Russia based on their popularity. The New Year tops the list, but Russian-speaking users of Twitter are also happy to celebrate Defender of the Fatherland Day, International Women’s Day, Victory Day and Halloween. The study findings have been published in PeerJ Computer Science.