I was reading an article a few minutes ago.
From the earliest we can remember, we are compared to others. As kids, compared to your siblings with respect to behavior. As you start going to school, you're compared to other kids at school with grades or popularity.
By the time we are adults, it is etched into us that we compare ourselves to other people. To be happy, we need to stop comparing ourselves to other people. There will always be somebody more successful than you, richer than you, more good looking you, etc.. By comparing yourself to others, you will keep lowering your self-esteem and not be happy with what you have. There is a line between striving to achieve more and not being happy with what you have. You can strive for more and be happy with what you have.
One of the most difficult things in life is stop doing this. I struggle with this on a daily basis. I find myself feeling envious of others even though I'm happy for them at the same time. I hope to get better at this as I grow older.