Rivers usually bring great ideas and water for irrigation. Egypt would have never been as great of a civilization if it had no river to use to make crops and then Egypt would be just another part of the Sahara desert. Mesopotamia would have never succeeded without the help of the Tigris-Euphrates rivers system to irrigate and make crops. Crops were incredibly useful for trade food and taming animals. If the two civilizations were not in river valleys, they would never have grown crops and would have perished sooner.
The two river valleys helped the Egyptians and Mesopotamians to travel to the sea and to other parts of their kingdom. It would take longer to travel to lower Egypt from upper Egypt and worship at Luxor. It would be difficult and dangerous to travel from Mesopotamia to the red sea on land due to the continuous wars going on. Without trade, Egypt would not have done as well, as they made large amount of profits selling slaves, papyrus and lotus perfumes, and other items of worth. Mesopotamians would have never received items of interest and would not have thrived, like the Egyptians had. Once again, if they were not in river valleys, they would never have traded and traveled from one place to another.
Rivers have also caused problems and gave people a different view of life and who has the best race. If not for rivers, the Egyptians might have never met the Greeks and Romans who took their ideas and their land and eventually ended their great civilization. The Mesopotamians wouldn't have had so much wars about who rules Mesopotamia.
Since their rivers flooded uncontrollably and