Most of us were raised to be very outcome-focused and driven by other people's opinions of us. Research showed that we most people would rather get paid half their salary if only everybody else is earning even less. Other research showed that we are happy with what we achieved until somebody else achieved even more. We take people for granted and feel much happier if we take a minute and appreaciate what we have now.
"The true mark of maturity is when somebody hurts you and you try to understand their situation instead of trying to hurt them back" http://justgetideas.com/free-most-best-short-daily-positive-and-inspirational-quotes-about-life-and-change/