I was saddened a bit by all the responses. Even though the OP questioned the beginning of a fantasy on his part that a companionable woman's smile may have meant something akin to "I like you", the low likelihood that it meant something romantic doesn't mean that it was meaningless. As hard as it may be to believe, providers and customers are not the only ones whose business relationship requires appropriate boundaries, yet non-business relationships frequently grow out of such "limited" business situations. For example, hundreds of millions of Americans go to work every day with members of the opposite sex (and their own sex) and deal with feelings, desires and fantasies that involve persons who are "off-limits" due to employer-employee status. I know my job would be a lot less fun to go to if it wasn't for personal relationships with folks who I work with and supervise, likewise with clients, vendors and others who would be completely inappropriate for me to have a romantic relationship with. Yet that is not a reason to write off our feelings for each other as imagined because its just business.
There are some providers (not on TER, of course) who think of themselves as selling and customers ( not on TER , of course) who think of themselves as buyers of access to another another person's body for physical gratification. The great majority of folks (maybe even some on TER) are in the business of fantasy /entertainment . It's a fantasy that requires certain boundaries, emotionally and otherwise) but that really isn't all that different from others who market or consume entertainment. Action movie stars are actors, not mercenaries; they are not the character they portray. Moviegoers are folks seeking some entertainment, free of distraction, that takes them away from their own lives for 100 minutes; they are not ghouls, etc. The only difference is one of degree. The fantasy world of TER involves letting down a lot of boundaries which in exchange requires thicker walls around those things that remain "off limits". When the fantasy is over, the clothes go back on, the actors part company and the walls can come down.
So when Leon turned around from "halfway down the road" and came back with that supposedly all-important envelope, they met under a somewhat different set of circumstances and rules . Leon turned around because it was important to him that he not be the kind of person who would take advantage of that sort of situation, especially to the disadvantage of someone who he has a relationship with that extends, within limits, beyond naked gymnastics. She likely spent the time between his driving off and coming back up the drive dealing with the dozen different thoughts and feelings about the missing envelope, all the different permutations of should I or shouldn't I. So, for a moment in her doorway, she got to see a part of Leon that is so much more intimate than seeing him without clothes, and she smiled the smile that comes from within, the one Leon had never seen before and may never see again, a part of her that was so much less mercantile, so much more personal, than seeing her without clothes on. A moment of I SEE YOU.
It doesn't have to mean that she wanted to have babies and buy a place in Sarasota with Leon but if we cant celebrate those moments rather than writing them off as having no meaning beyond that fucking envelope, then the planet is in bigger trouble than I thought. Or maybe this was all my fantasy .