“In the dead of winter, the man shook hands with a snowman, and warmed him with his scarf. The snowman melted, and the man froze.”
This reminds us of two key concepts. First is of course impermanence, the transience of life and things. Secondly, it reminds us of the inherent nature of everything. A snowman is frozen water of course, and is meant to stay cold. When it is warmed, it melts and is no longer. A human is meant to stay warm, and when chilled, it freezes and is no longer.
There are sometimes things we encounter that we would like to change, but it is futile. For example, we may think a baby tiger is cute, but it will likely grow up and kill us. That is the nature of the tiger.
With that said, it is also not correct to think that people cannot change their behaviors or personality. The mind is very powerful, and with humans having such a powerful conscious and conscience, we can change our perceptions and drastically alter our behaviors and habits. This can be good or bad. When we are mindful of this, and use it to improve our lives and the lives of those around us, we can achieve great things.