No one likes you for your clothes, your car, your possessions, your title, or your accomplishments. Those are all "things." People may like your things — but that doesn't mean they like you!
(Sure, superficially they might seem to like you, but superficial is also insubstantial, and a relationship not based on substance is not a real relationship.)
Genuine relationships make you happier, and you'll form genuine relationships only when you stop trying to impress and start trying to just be yourself.
And you'll have a lot more mental energy to spend on the people who really do matter in your life.
(Idea derived from Jeff Haden)