You’ve just offered assistance to one of your guests or customers, and they say, “Thank you!” In that very moment, what is your response to this expression of gratitude? Perhaps you reply with the traditional “You’re welcome.” But perhaps you’re in the habit, instead, of saying “No problem” — or “Not a problem” — or “No worries.” While these latter responses might be appropriate for more informal personal settings, there are very good reasons to avoid them in the context of customer-service interactions. Here’s why ….