For people who are not familiarized with the Greek culture, some of the Greek names may sound a bit pompous and hard to live up to like Athena (Goddess of Wisdom) , Ares ( God of War) or Aphrodite (Goddess of Beauty). In Greece though they are common names and people don't seem to be pressed by the weight of their names as it happens in other places. Which is a very good thing.
The not so good thing is that, according to tradition, the new born is named after one of the grandmothers if it's a girl and grandfathers if it's a boy. Greek parents rarely consider the option of naming their kids with a different name. This is a moment of strong friction and serious discussions in the family with logical arguments like "My mother's name is better than your mother's name".
By now the grandparents already started putting pressure on the couple in order to make sure they will chose the name from their own side of the family. If that doesn't happen these arguments may end up bad and families may cease to talk to each other for years just because "You chose the other grandmother's name for your kid".
Another explanation I heard recently is that it all has to do with the money. Couples chosen the name from the more wealthy family, the one who can provide better for the kid.
So, overall, this is the reason for which, from all the beautiful names that Greek history and mythology provide, 90% of Greek males are called: Giorgos, Yannis, Konstantinos (Kostas), Dimitris or Nikolaos(Nikos) while top five Greek female names covering probably almost the same percentage of the population are: Maria, Eleni, Katerina, Georgia and Anna.
Since Thessaloniki is the birthplace of Agios Dimitris you will find here a particularly high density of Dimitris and Dimitra names.
Greek Church doesn't see with good eyes the names that are not of christian saints so if you feel adventurous and want to name your kid Electra or Orestis you might have the surprise of your life but then again baptizing a child in Greece is an adventure on it's own so I think I'll leave that for some other time.