In the third aliyah of Parshas Vayeira, we learn about the destruction of Sodom. Although the malachim (angels) are treated with hostility from the start, the fate of Sodom is not sealed until after Lot tries to convince the people not to act in a despicable way. The people do not want to hear rebuke, and say that Lot has no right to speak to them in that way. This character trait is what blocks a person from teshuva (repentance) and self-improvement, as they will never be open to change. Lot originally saw this in Mitzrayim, and lived in Sodom because they had a similar attribute, one which he still carried with him even after he was saved.