GUIDANCE    Conversation face-to-face: That's what you want when an exchange – a romantic one, a social one, a commercial one – is brewing. Person-to-person transactions are anchored in trust. Personal approval encourages agreement of any kind – whether it's a business agreement, a love affair, or a friendship. Yes, we have friends we don't approve of, and we have passion for someone we don't even like, occasionally, and we buy from or sell to people we don't want to see again. But ongoing excha...