Abram and Lot ascend from Egypt, returning to the southern part of the Land of Israel, the Negev. Strife breaks out between their respective households, and Abram proposes that they separate. "The language in which he addresses Lot is clear, firm, and polite." (Alter)
Lot takes what he sees to be the better territory - "all the plain of the Jordan, a lush, fertile area large enough for his flocks and herds." (Steinsaltz on v. 11.) Following this, God promises the Land of Israel to Abram - and also promises progeny.
The text reports Lot's choice of land from Lot's own point of view. "And Lot raised his eyes and saw the whole plain of the Jordan, saw that it was well-watered, before the Lord's destruction of Sodom and Gomorrah, like the Garden of the Lord, like the land of Egypt ...". (Alter's translation.) That's a striking, and very ambivalent, pair of similes there.
Lot sees the physical terrain, but not the moral terrain. Verse 13 tells us that "the people of Sodom were very evil offenders against the Lord." And this is a good place to point out the importance of sight and attention in the Bible.
In the very next verse, the Creator tells Abram, "Raise your eyes and look from the place where you are ... for all the land you see, to you I will give it and to your seed forever." Both men "raised their eyes", but only Abram did so under God's instruction. Where Lot looked, he saw abundance; where Abram looked, he saw potential, as revealed by the Divine voice. And along with the promise of the land comes God's other promise to Abram: that the land will be filled with his children's children.