When you ask for directions to get somewhere, chances are you will be getting correct answers. But asking for restaurant recommendations is a completely different story. Actually, it is highly uncertain that you will hit the jackpot.
One of the reasons for this, is because usually people on holiday often go unprepared and ask for recommendations from their hotel staff. Unfortunately, some times hotel staff either do not have enough knowledge or give biased recommendations because they get commissions for referring guests to a specific establishment. On the other hand, there are some hotel concierge who are highly professional and knowledgeable of the local scene and can send you to the most amazing places, where tourists never dream of going.
One way to spot who is knowledgeable is to ask a lot of questions. For instance, don't ask which restaurant you should go to, instead ask for the best fish restaurant, or the best traditional restaurant, or the best upscale restaurant. If you get answers, then ask for the second best in each category (in case there is no availability).
If by that time, you do not get kicked out by an annoyed concierge, you will get an valuable list worth gold. This is how you will figure out if that person is willing to go that extra mile and provide good information.
If they stop at the first name, they insist on it and they try to oversell it to you, you will know there is something going on. It is such a shame to let a tourist trap spoil your valuable vacation time.