For one I hope that I do not actually evolve into a wild beast in the way that Buck did. Some of the other aspects of Buck's evolution and maturation are more appealing and more interesting when looking at it from a human perspective.
As Buck leaves the pampered life at the judge's home, he learns very quickly. He is exposed to all sorts of new people, new dogs, new weather, and a very different way of life. He adapts to each situation and newcomer in turn becoming more worldly and gaining knowledge and using his new understanding effectively. I would hope that I too can gain more knowledge as I grow older and encounter new situations that I can learn from and then use that newfound knowledge effectively.
Another aspect of Buck's evolution that is interesting is the way that he becomes more self aware and seems to grow more capable of reflection and insight into his own character and desires. So too I might hope that I can be more self-aware and be able to change to fit new situations effectively and better follow my own desires in order to be happier.