You create a first impression within the first 30 seconds of greeting someone. How you greet them will set the tone for how your relationship with that individual will develop. If you do not take the time to greet them properly it could leave them with a negative impression of you whether you meant to approach them in that manner or not.
Have you ever been greeted by someone who did not make eye contact or seemed too busy to bother? Greeting someone like this sets up an interaction that will most likely have a similar tone, ultimately losing the opportunity to strengthen a good connection with that person.
Everyone likes to feel as though they are important; greeting someone with a smile, asking them how they are doing and actually waiting to hear their response is a great way to create a good connection. This rule applies regardless of whether you are meeting someone for the first time or if you've known them your whole life.
I found this at a New Empire Group blog dated August 17th 2011. Couldn't have said it any better.