Why are people different?

Hello :)
I have been reading, Mindsets, by Carol Dweck. It elucidates the two ways that people think causing them to be different from each other. People with a fixed mind believe that talent and ability come naturally to you. Either you are good at something or your not. Those who are not smart have to put in effort and work. They worry more how they are judged than learning. People with growth mindsets believe that ability and talent can be developed through hard work and perseverance. Like the fixed mindset, they also suffer from failure they do not let that crush their hope. Effort eventually leads to success and criticism is needed in order to grow. Dweck mentions that it is not bad to have a fixed mindset, but that their confidence is limited compared to the growth. Is there any positive elements in the fixed mindset? I discovered that I have a mixture of both. This novel is interesting because it has allowed me to discover more about myself. I do believe that how you think will contribute to your success but sometimes we do have to discern reality as it is. If we really want to strive for something, we need to prepare for the worst and keep moving forward :)