Self esteem - that word is used so much, it is almost a cliché. But nevertheless, in my experience, both personally as well as professionally, it is key to feeling content and grounded.
It is not, as is commonly thought of, about thinking one is better than someone else, superior in some way, or at the top of the heap.
It is much more about feeling an acceptance of oneself – a quiet confidence which cannot be dented by others' opinion about us.
When we feel bad about ourselves, then someone can easily say something to us which buys in to our own harsh feelings about ourselves. For instance if we feel that we are not good enough in some way, and judge ourselves for not being good looking enough, rich enough, thin enough etc etc (the list goes on), then if someone says something or even reacts in such a way that we interpret their action as being because we are not good enough, then we are always at the mercy of other people. The barometer of our happiness depends on outside reactions rather than our inner core belief and contentment with ourselves.
This does not mean that we never strive to better ourselves, but it does mean that we feel contentment and acceptance of ourselves at all times, which cannot be shattered by someone outside of ourselves.
Self esteem can also be viewed as self compassion – accepting ourselves as being ok, being good enough, despite not being the best of the best. That way, no one and nothing can take away our inner sense of ourself and our stability.
In other words, we are in control of how we feel about ourselves – we are no longer at the whim of other peoples reactions.
Therapy can help in viewing ourselves throughout more compassionate lenses and ultimately giving us the power to regulate how we feel about ourselves, regardless of circumstances.