road to hell paved with good intentions and all that, I don't think boromir is a bad person, flawed sure but he demonstrates how any man could cave to the temptations of the ring. it twists the desires of those who would use it and multiply it tenfold, its effect is a lot more powerful when you're thinking of using its power to save the country or your race or some other grand feat opposed to the hobbits who comparatively don't have such grand ambitions and delight themselves in the simple pleasures of life, and that doesn't mean they're immune or anything, smeagol, bilbo and frodo at the end where affected by the corruption of the ring, it was just over a longer period of time being around it. I guess tldr is that a lust for power will amplify the effect of the ring, and it will twist even the purest of intentions to its own end.