Dating often begins with choosing a person to take out. They may be a co-worker that has been friendly in the past. That friendly neighbor with the large dog might be a possible pick for a date on Friday night. Perhaps the friendly person working at the local pub might be a person to ask out. Each one of these people has one thing in common. They are all friendly. Being friendly is an attractive attribute to many people.
There are few people willing to date someone that is surly or never smiles. If given a choice, these people might never get a date. There are always desperate people somewhere that willing to take anyone out that says yes. While this is fortunate for surly people, it might just be easier to smile once in a while. Once someone notices that smile, a date for Friday night might be a reason to keep smiling.