Your other senses, taste and smell, will be piqued too I bet and olfactorally you will experience many non-city aromas; some of which you may recall from home: basil, wild rosemary, wild thyme, lemon blossoms, orange, laurel, dandelion, cinnamon, sage and apple. Others may be new to you, such as those unique to certain locales: Mastic, poppy, olives, figs, chamomile or the delicious smell of grilled octopus from the nearby seafood tavernas or ouzopolia. I always order the grilled octopus, not the sauteed. An early afternoon sit down with an an ouzo and octopus meze (appetizer) will have you wondering why you haven't done this long before!
Much later that night, will come your evening repast, hopefully, at least once on the seashore, or around the small limani eating fresh fish at reasonable prices. Fish has gotten expensive over the last few years and what with over- fishing its not going to get any cheaper. Plenty of local people fish on Greek islands standing on the shore with rigs as varied as a piece of nylon filament with a baited hook to snorkeling and spear fishing. You can catch fish and if you do, most local tavernas will grill it for you for a small fee. If one wont, move to the next. It works every time! Ask for plenty of lemon too!
For dessert fancy cakes are only available if you seek out a patisserie or zacharo-plasteio. Tavernas usually only have the Turkish style sweet Halva for dessert and fruits such as watermelon (kar-pousie) and cantaloupe (peponi) to freshen ones palate in the summer. Halva made mostly from farina and almonds can be a remarkable confection, as light as air, or a tragic bore. I prefer mine with cinnamon and lemon.
If the waiter/owners really like you they may treat your party to a platter of such fruit for free. They may not. If they really really like you they will also offer shots (sphee-nakia) of after dinner liqueurs with the fruit for free too! These are nice way to try aperitifs unique to each island bottles of which make nice gifts and souvenirs. (below right, wall mural from Acrotiri in Santorini - Athens National Archeology Museum)
Unique to Greece, I think you'll also find is the smell of incense from a Greek Orthodox Church and perhaps you'll even wonder why are there so many of these churches everywhere? The reason is that most were built by families or individuals - sailors mostly - for the Greeks are a sea faring people and particularly so in the islands. Each church is devoted to a specific saint to which its builder wishes to thank for blessing received. Much like the ancient temples devoted to Artemis or Athena or Apollo. Some small islands have 400 or more such tiny chapels and all are up kept by the villagers or builders family. Many you will find unlocked and many you will find locked. If you light a votive candle be sure and place it upright in the sand dish and leave some change to help the upkeep.
Your taste buds too will have to adapt but rest assured the Mediterranean diet is among the healthiest. Its reliance on olive oil, fresh vegetables, fish, yogurt and honey should be taken advantage of in their natural surroundings. Greece has more kinds of honey, types of grapes and varieties of olives than any country in the world and has had, for thousands for years. The islands, to varying degrees, possess them all in abundance.