We also can't ignore that the ring was no mere object, but actively working to twist, corrupt, or take advantage of any weakness in those around it in order to further its own objective of getting back to Sauron. With his extreme sense of duty and desperation, the ring found something in Boromir it could exploit and, in a moment of weakness, he wasn't strong enough to resist its pull. He was genuinely heartbroken when he came to his senses and realized what he had done. The way they portrayed Boromir in the films is one of the few things I don't find any fault in. I honestly don't think they could have done him any better and can't see anyone else in that role other than Sean Bean.
I agree with every point.
@paranoid marvin I don't dispute that Boromir feels more human. How many of us can identify with a prophesied king? Aragorn lived an unnaturally long life compared to the men of Gondor. He was of purer royal blood of Numenor than Boromir.
Also, Boromir was working without some critical knowledge. He had no idea who Aragorn was nor even of Aragorn's existence prior to going to Rivendell. Aragorn served as a hired sword in Rohan under Eomer's grandfather, Thengel. Then Aragorn served Boromir's grandfather, Ecthelion, for maybe fifteen years. During that time, Aragorn went by the name of Thorongil. By protecting Ithilien, just like Boromir and Faramir in the next generation) Aragorn rose to be the chief captain of Gondor (except for Denethor, Ecthelion's son and Boromir's father). Aragorn's Numenorean blood, in addition to giving him a longer life, gave him wisdom and insight lacking in normal humans. Denethor and Faramir also had this Numenorean perceptive powers that Boromir decidedly lacked. Most likely, Denethor pierced Aragorn's identity at this time. They were accounted the two greatest captains of Gondor, but Aragorn was more loved and judged more capable.
Boromir was born during Aragorn's stay in Gondor... and Aragorn would might likely have seen Boromir as an infant. When Boromir was two years old, Aragorn took a flotilla and surprised the great fleet of the Corsairs of Umbar. He burnt their entire fleet at anchor. It would take Umbar another generation to fully recover their strength at sea. They used this threat of a "Fleet In Being" to keep many of the lords of southern Gondor to stay home to protect their lands instead of going to the defense of Minas Tirith. Fortunately for Gondor, Aragorn once again destroyed the power of Umbar on his way to relive Minas Tirith. Anyway, after his first victory, Aragorn left Gondor. People thought is was to avoid a confrontation with Denethor, Ecthelion's heir, but it was because Aragorn had accomplished what he wanted.
So after Denethor succeeded Ethelion, he suspected that Aragorn was out there scheming to steal the throne of Gondor, but he never told Boromir nor Faramir. He knew Aragorn and Gandalf were on friendly terms and suspected them to be in cahoots to remove him from power and deny Boromir his birthright.
While serving in Ithilien or even at court, Boromir and Faramir probably heard the exploits of Thorongil. Boromir never equated Thorongil with Aragorn and certainly Aragorn nor Gandalf ever told him. I do not know if Aragorn ever told Faramir, but I suspect after the revelation of Denethor's refusal to acknowledge Aragorn, Faramir's revival at Aragorn's hands, and the triumphal retrun of the king that Faramir was perceptive enough to figure it out.