Why do people celebrate events like weddings and birthdays?

The past few decades have seen an increasing frequency of people celebrating memorable events or occasions like graduation ceremonies, weddings, and birthdays. The principal reasons for this trend are twofold. First of all, people nowadays have more savings to spend on celebrations - which normally associate with recreational activities like parties, dancing, or group meal - while our predecessor needed every piece of a penny on living essentials such as foods or clothes. As the productivity of the entire world rises and machinery takes over most of the production processes, we, humankind, are able to relieve ourselves from fighting for foods and chase leisure activities instead. Hence, since they are undoubtedly the happiest moments in our life, celebrating weddings, birthdays, and other similar events have become reasonable. Further and even more importantly, though, celebrating special occasions creates shared memories among families and friends, which is vital for us since we are social animals. The same memories of special moments that we share with family members or friends will become topics anytime we meet each other in the future and will be the bond that significantly improves relationships among us. It is irrefutable that the milestones of our life, such as graduation, marriage, birth would be the perfect moments to hold the mentioned-above celebrations. Celebrations, therefore, like a strong and vital glue that sticks the whole society together. By way of conclusion, having the ceremonies for special events in our life is not only one of the methods that humans use to relax, but also vital for us to maintain the connection with our loved ones.