Although both are arid and riverine, Mesopotamia (a region now called Iraq) both challenges and nurtures residents while Egypt provides a limitless cradle.
For very disparate reasons, both sites pushed their inhabitants to develop mature social complexes which reflected their geographic environments culturally. Egypt had idyllic geography. Located along the Nile, which flowed with nutrient-laden water and lots of fish, it had tremendous natural resources (except wood) and very rich soil. Although there were annual floods, they were very predicable and less violent than Mesopotamia's unpredictable and destructive overflows. In addition, the Niles' floods would wash the soil with a layer of organic material. This yearly deposit of mulch was agriculturally beneficial and meant that Egyptian farms could never overcultivate.
This spring was largely invulnerable to raids, as it was protected by vast deserts to the East and West and cataracts along the Southern Nile. This also made import slow, though, as the only ready way to access Egypt was to drift along the Nile via air and/or water currents. Upon encountering a cataract, a ship could either be taken onto dry land and carried beyond the cataract or unloaded so that another ship (already over the cataract) could be used. However, this setback was greatly outweighed and Egypt readily and rapidly fostered a tremendous and prolific civilization.
An obsession with immortality and worship dominated Egyptian culture.
While initially only Pharaohs (equivalent to a king, and considered only one degree of separation from divinity) could attain immortality, the afterlife was rapidly democratized and after only a few generations the entire populace could cheaply and easily attain immortality through a lifetime of worship, respect and good form.
Strikingly enough, it was believed that heaven was much like the land of living: essentially, Egypt itself was the same as heaven.