Competition within any species, over anything, results in better organisms. This happens through the adaptation of some organisms of the species in order to outcompete the competition. As human beings, we face competition from fellow humans, whether it's for food, business, space, resources or companions. This competition helps us develop a better skill set or make changes to our lifestyle and ways of functioning to win over the competition. For example, if we are competing for the same job, a candidate with a better skill set will likely triumph. The only way others can defeat him or her is by developing equivalent or better skills. This will help other candidates become a better contender. A competition for customers will make us a better engineer or manager or producer. Overall, the competition will help us evolve and thus become better in every sense.
Hope this helps.