Working the sushi counter is all about being hospitable and sushi chefs are some of the most humble humans on the planet. But when you're at the counter, Masa has a few polite recommendations.
In Japan, most sushi operates on an omakase ("I trust you") system where the chef serves whatever he feels like, but at Uchi, the focus is more on the customer's tastes than the chef's. Don't ask "what's best?". Instead, offer a few examples of your preferences and you'll be rewarded with fish you'll actually enjoy.
And never ask what's fresh. If the place is legit, everything's fresh or else they wouldn't be serving it.