When you frown at other people, you rob them of their happiness. They ask themselves, "What did I do wrong? Why is he or she mad at me?", and they lose confidence. Frowning at other people is tantamount to taking your anger out on them. No one has the right to air frustrations on one's fellow man. On the other hand, a smile is an act of compassion, whereby you brighten your fellow human's day.
Even if a crow wears a coat of elaborate white feathers and walks around saying "gobble, gobble" all day long, he still won't be a turkey...
Whenever a crow tries to imitate a turkey, he's doomed to frustration, for he'll never succeed. The same goes for humans.
People imitate others for two main reasons: First, they have low self-images and lack confidence in themselves; and second, they're incognizant of their own individual talents and aptitudes.
One of the most important points of spiritual awareness is the knowledge that you are unique. The Almighty has given you personal qualities and abilities that no one else in the world has, so that you can perform your own special mission on this earth. When you try to imitate someone else, you fail to accomplish your own task, and ultimately become frustrated and unhappy. Being yourself and cultivating your own special skills are the key to happiness and fulfillment.