I'm not sure they are absolutely essential. I mean, if I have a birthday party with friends, then sure, why not have some music and dancing; it's a great way to have some fun and relax with friends. However, if I want to talk or catch up with friends, then I don't think they are essential. Having people around me that I care about while having a party in a restaurant or the park is just as fun as having one with music and dancing at my home. The most important thing is to have a laugh and enjoy yourself.
友達と一緒に誕生日パーティーをするなら、音楽や踊りを楽しむのもいいかもしれないけど、友達と一緒にリラックスするために必要なのかはよくわからない。友達と話すことや近況を聞くためには、必要ないと思う。自分が大切にしている人たちと一緒に、レストランや公園でパーティーをすることも、家で音楽や踊りを楽しむのと同じくらい楽しいと思う。大切なのは笑いを共有し、楽しむことだ。