Is the grass really greener on the other side of the fence? Is that persons life really Better than yours? Would your life really be more joyful and fulfilling if you achieved X,Y and Z or if you owned the next gadget, toy, house, car etc?
Sometimes all we need is a reminder that what we have right now is enough and by striving for more and better we might actually be missing the best stuff.
Pause for a moment, close your eyes, take a deep breath and smile.
I hope the world smiles back at you.