We as humans have ideas that what we have isn’t enough, that what someone else has is ‘more’ when it is just different. This can lead to consumerism and all manner of destructive behavior, and is generally regarded as not a good thing.
For example, society and the media both encourage us to covet romantic love, devaluing family and platonic love and elevating romantic love higher than others by telling us that we should all have it, that without a romantic partner we are incomplete and alone. But most of us have something just as good--deep enduring love of family and/or friends, and as long as we have them, we are not alone. The enduring love of family or that best friend over the years is worth so much more than a high school boyfriend who gets forgotten a few years later.
We have an innate desire to be what society considers beautiful, whether the current standards prize symmetrical or asymmetrical features, long, short, straight, curly or wavy hair, sleekness or curves, spareness or bounty of body. But most of us already have what we need, and likely what someone else desires and considers beautiful--a reasonably strong healthy body with working appendages and functioning five senses.
In my own life, I was a rather isolated kid, reading countless books about ‘normal’ people, and naturally wanting what they had: three or more friends (and even more casual acquaintances) they saw multiple times a week, adult role models other than their parents, parents who cared if their kids were normal, and the delicious thrill of blowing off prom to go to a laid-back anti-prom party. I tried to be thankful for what I had: one or two friends I saw a couple times a year, a large family with whom I was friends, two sets of living grandparents, not to mention basic necessities of life such as enough food, clean water, and a warm house.
We should be content with what we have, but at the same time our drive to want more can lead to vast improvements in our own lives, in society and sometimes eventually the whole world. Womens’ dissatisfaction with the current laws in the early twentieth century resulted in their right to vote, own property and more. English colonists living in the thirteen colonies, dissatisfied with their king’s broken promises, wrote a certain historical charter and became Americans. Poor kids from uncaring families driven by a desire for better, put themselves through college, marry and are better mothers and fathers than their own parents were to them.