From HBO series Westworld, "A cornerstone is a specific memory tied with a single event which is used as a base to construct a host's personality". The memory that is used for the few key characters is often a sad negative memory that later built a strong personality, such as Dolores, Bernard and Maeve.
From Pixar animation Inside Out, a personality is built based on a few core memories. Joy (1 of the emotion) later discovered that behind each core memory, there is a sad moment that makes this memory much more impactful and becomes the key memory that builds a person's personality.
I think both were true, our personality & characteristic is formed by our experience of the world, our memories. Very often these impactful memories is backed by a sad story/moment.
At the age of 40, I realised that I'm often attracted by songs that sing about the feeling of loneliness, sad despair, stress, etc. Perhaps after all the experiences that I have been through, these feelings are more genuine and resonate better.
What do you think?