Insecurity is pretty common in our modern society. Most of us are “infected” with it and allow it to affect everyday life. It is everywhere: in classrooms, in the workplace and within our most intimate relationships. Why are we insecure? It usually has nothing to do with our "superior" classmates or "more productive" co-workers or "better half." The problem is usually rooted within ourselves because when we assess these situations, we look inward and perceive our own inferiority.
If we consider each situation carefully, we will have a better idea about how we can change our thinking to improve our opinions of ourselves. Usually in a classroom, when we see another student who is answering each question quickly and correctly, we feel incompetent in comparison—as if we don't belong. But what we forget is that we all deserve to be there. We are there in the first place because someone thought we were apt enough to master the same material and contribute equally to productive discussions. So, relax. You have another class in an hour in which to demonstrate your expertise.
In our work environments, there are always co-workers who seem to be regularly praised by their boss. If we decide to brood over their success and feel insecure about our own abilities, we are only wasting our own time. It's that simple. We are both working there because every employee offers a unique skill set and perspective that was deemed valuable upon hiring. Maybe, if you focused a bit more on yourself than that person, you might be the next in line for a raise.
In a relationship (speaking from a male's perspective), we tend to feel insecure when our partners asks for advice from others or hang out with other guys. What we really need to remind ourselves when we feel jealousy creeping in is that they chose us. They are with us because they want to be. If we tell ourselves that, we can often feel better. The same goes for the opposite sex, (as far as I know).
We can find the solution in the fact that our perceptions alone cause a feeling of inferiority. The moment a person realizes that if they change the way they think about and respond to these situations, they can rest easy knowing that they're only doing their best to improve as a person. Achieving satisfaction in one's self is the primary way to quell a sense of insecurity. When a person is satisfied with their work, they are much happier. These kinds of people tend not to compare their final products to others’ because they understand that everyone had a different solution to the same problem. To compare only the two end products would be unfair to both parties as they are inherently different and unique in their own right.
Insecurity is an ever-present demon in our lives. But, it doesn't have to be. The day we accept ourselves for what we are, believe a little bit more in our abilities and are satisfied with the person we have become, we take a giant step to improve our mental health and relieve ourselves of unnecessary stress.