I find this question quite intriguing. There could be different reasons for a song to be viral and recognised by everyone from a particular generation, even when looked at from a psychological lens. Just at the top of my head, I could think of resonating emotionally with a song to be the main reason why a song becomes universal. Music has the power to evoke such strong feelings in an individual and once in a while, such songs come our way that stay forever. I am taking two directions and dissecting this question, I believe a song becoming viral is different from a song being iconic. Viral songs are short-lived, and there could be different mechanisms for the explanation behind that such as the mere exposure effect or the idea of ‘fitting in’, the social influence of staying with the trend are some of the possible explanations behind it. These songs don’t have to have the oomph factor to get viral, especially in this century. On the other hand, iconic or universally popular songs have an affective, behavioural as well as a cognitive appeal to them which is usually because of the most fitting lyrical and musical amalgamation which brings out the emotions mimicking some sort of never experienced nostalgia.