Greece

Greece was never colonized, so the question is inapt.

Assuming the question is referring to the Ottoman Turkish Occupation of Greece, a distinction must be made between imperial territories and colonies. An imperial territory is part of the mother country and its citizens are direct citizens of the mother country with no legal distinctions, save those that might be applied in one region and not another (similar to the various states in a federation like the United States). Of course, the fundamental difference is that Greeks did not choose to be part of the Ottoman Empire and fought for nearly a century to become independent again.

The Turkish Occupation had an incredible effect on the development of modern Greece.

Economics: Probably the greatest effect was in the lack of modernization within Greece during the 1700s and 1800s. While much of Western and Central Europe was modernizing at a breakneck speed, especially with the Industrial Revolution, Greece, as an Ottoman possession "stayed still". The attempts by Greeks in the 20th century to industrialize and catch up with the remainder of Europe have had some success, but Greece's economy is still very inefficient when compared to Western Europe, especially as concerns infrastructure, resulting in Greece having consistent economic problems to this day.

Greco-Turkish Relations: As any Greek will tell you, there is no love in their hearts for Turkey, the successor to the Ottoman Empire. The two sides parted bitterly after several different wars and current disagreements over the island of Cyprus. The current problems between Greece and Turkey are a direct result of the Ottoman Empire's control of Greece.

Greek Ethno-Religious Identity: Minorities in the Ottoman Empire were recognized by their religious affiliation in the Millet System. This meant that Greeks who converted to Islam were no longer Greek, but Turkish, and conversely, in order to remain Greek, you had to affiliate with the Greek Orthodox Church and be actively religious. This has created a mindset in Greeks that being Greek is not really just an ethnicity, but also has this religious component. While being a Greek Atheist is not really an issue, being a Greek person of a different religion, especially a Greek Muslim or Greek Protestant, rubs many the wrong way. The sentiment that "to be Greek is to be Orthodox" comes directly from the Millet System.

The Persians conquered Greece, by doing so, abolishing slavery and bringing equality and Persian culture to Greece.

Another View:

The above is a quaint viewpoint as the Persians themselves owned a few million slaves, and brought a goodly number along in their invasion force as cooks, servants and prostitutes.

And of course the Persians did not conquer Greece. They were defeated in their invasion - after an initial defeat of The Ionians in Asia Minor 499-493 BCE and a naval victory at Artemesion 480 BCE, they were defeated at Salamis 480 BCE, Plataia 479 BCE, Mykale 479 BCE, Eurymedon $66 BCE and Cyprus 450 BCE plus several lesser battles until they gave up their design on incorporating the Greeks into their empire after a struggle lasting 499-450 BCE in the Peace of Callias 449 BCE. And then a hundred-odd years later Alexander the Great brought Greek culture to Persia, not the other way around.

Thermopylai was a minor holding action of a few days in a fifty-year war - it changed nothing other than to become a legendary story of the Spartans and Thespians who sacrificed themselves covering the withdrawal of the rest of the Greek contingents at Thermopylai.