There are many situations in life that can be seen by different perspectives,the classic example of this is whether you see the glass as half full (optimist), or half empty (pessimist). Or, as my son the math/physics genius says, the glass is twice the size that it needs to be. I believe that your perspective comes from a combination of nature and nurture.
The real question is, what are you going to do about it? No matter what your perspective is, you can allow yourself to just stop at the point where you make your assessment of the situation, or you can take that assessment and let it guide your actions. You can gloat that you have half a glass of milk, while it slowly goes sour, or you can drink up, and enjoy the refreshment and the nutrients therein. You can lament about the unfairness of the world that only gave you half a glass of milk, or you can take action to get more milk. If you believe that the glass is twice the size it needs to be, you can wonder about the strangeness of the world and the choices people make, or you can either fill the glass the rest of the way, or find a smaller glass.
This can be applied to much of life. Your perspective may define the choices that you see available to you, but you always have choices. Each choice will bring different results. You may not have available choices that lead to the results you most want (eg, there may not be a miracle cure available), but there are still choices. If there is something you don't like in your life, how do you see the situation? What are your choices? Which one will give you the best results? Which one will you choose?