Hole-in-the-walls are the heart of cities
Turn a tight corner, go downstairs, slide pass someone back-to-back to be seated at a table amidst a din of overlapping conversations where you're holding a well-worn thick paper menu that has 5 options to choose from. A server comes, takes your order, snatches the menu back, brings the food over near-instantly as if they could read your mind, and you take a bite of one of the best meals you've ever had.
It's a hole-in-the-wall.
The combination of being small and hard-to-find is what makes hole-in-the-walls the spots I seek out most. Being small lets the chefs/bartenders focus on quality ingredients and recipes. Hard-to-find gives the finder a reward before even stepping foot into the restaurant and the feeling that they are part of the exclusive club that "found it".
Whenever I ask someone for a recommendation on where to check out, if they shift a little closer, lower their voice, as if to keep others from hearing privileged information, and start by saying "There's this little place that's a bit hard to find, but...", I know that this is gold.
For me, these spaces represent the heart of a city and if they go away, so does the city.