How could self-esteem be unhealthy?
It depends on what it is that makes you feel good about yourself. Do you depend on other peoples' approval to boost your self-esteem? Probably. Most of us do. What matters is how much.
Too much of what psychologists call contingent self-esteem is unhealthy. Think of it as handing our lives over to other people. They define our goals. They set the standards for our success. They judge us.
People who depend too much on other peoples' approval are constantly comparing themselves with others - often people they only know about through the media. They are overly concerned with appearances - maybe having the biggest SUV in the office park, keeping up with the fashions and inviting friends and family to their fancy house.
Those with contingent self-esteem can be more ambitious than people who are not driven by the need for other peoples' approval. But, generally speaking, it doesn't make them more successful. They are less resilient, more anxious and self-conscious. They are more likely to abandon their goals, or only set easy goals, because trying hard and failing is a serious threat to their identity as a successful person.
So what's the alternative?
We can focus on the rewards of living according to our values and feeling good about achieving goals that are important to us. We can do our best to shrug off unhelpful comments from those who judge us according to their own standards.