Like it or not, every contact you make, and really every person who see you, receives something from you. It's called an "impression." You can't prevent an impression from forming in the eyes of those who simply see you, but an even deeper, more complete, impression is formed in people who converse or complete some sort of transaction with you. You have to make an impression in some form.
Why not make a great one? Suppose you simply exude confidence? Suppose you show genuine delight at meeting someone? Or, maybe it's digging up a friendly smile for your server, even though it's been a really tough day. Dress for success, channel confidence and charisma from within and you will attract others to you in the best of ways. You are going to make an impression one way or the other.
Be distinctive. Be unique. Be remembered...instead of forgotten.