At times though we do meet people who inspire us. We learn good character traits by being in their presence. We may even practice them and make them our own. I think we all have models. That is what a guru is all about.
Smiling does make others feel comfortable. I do find it easier to smile when I am relaxed though and when I'm feeling free of 'issues' that come up in life. Sometimes though it is good to 'assume a virtue though we have it not.'
I'm not so sure I agree with you on all of this, Steve, all though I get where you're coming from. We have to realize the truths of spirituality as ourselves, and not merely imitate a teachers personality. That way our knowledge becomes personalized, and not merely a form of role play. As long as it's role play it will not be soul play. Imitating someone's personality has many subtle limitations. First of all, it is shallow. It is vain and phony even if it sometimes has agreeable results.
Now, for smiles.

My experience is that they have the most positive effect when they are genuine. A true smile comes from your whole being, a phony smile is calculative. It is a present wrapped with a beautiful bow but nothing inside.
When somebody practices an art like music or dancing they imitate models or a teacher. When they have conquered many of the tools that their model or teacher has mastered they then are a vehicle for the the souls expression.
Each flower unfolds and blossoms in its own way and time. When we begin to understand what path others are taking to that unfoldment we are indeed opening up to a universe of widening and growing expansive possibilities.