What have been key geography and historic factors shaping development of Eastern Europe?

Identify the positive and negative factor to the region and how it has impacted the regions culture and behavior.

There are many factors, but for the last 6-7 centuries with the exception of 20th century, Eastern Europe was under the rule of Ottoman Empire. That made all the nations in EE have been effected by each other, and with the Turkish culture. It also introduced Islam to the nations in Eastern Europe, which some of them still keep as religion. Other than that, stable rule over the centuries have developed Eastern Europe greatly, but in the downfall of Ottoman Empire, the EE have been the primary battle ground in European part of the Empire between the major players of the continent. Nationalistic ideas, caused by the French Revolution in 1789 fastened the disintegration of the Ottoman Empire, and caused riots all over the Eastern Europe. Nearly all the nations rioted against the central rule, and left the Eastern Europe in ruins.

Russian Empire's Panslavism politics also effected a great deal of the nations in Eastern Europe. Russian Empire used this as a way to interfere and often attack Ottoman Empire's territory, which also in return caused great deal of havoc in the Eastern Europe.