Don't get me wrong; I'm a massive Mann fan. I've seen Heat countless times and own Manhunter, Miami Vice, The Insider and Collateral on blu-ray. I found the first 2/3 of this completely riveting. James Caan was playing one of the most alpha characters in cinematic history. Then all of the sudden he spazzes out and goes into Terminator mode? I probably missed something but it just seemed like this one is missing some of the subtlety and nuance of Mann's later masterworks.
With his best friend/partner dead, the fact that he sent his wife away for her protection and no hope of realizing his life goals, his only remaining reason for existing was revenge prior to relocating and establishing a new and comparatively humdrum life. This is why he became an emotionless, vengeance-fueled kill machine. Sorry you weren't emotionally invested (or perceptive) enough to recognize and appreciate that.
They didn't really build the deep background friendship with his partner, it was more with Willie, so for him to give up his family just for his partner doesn't make sense, especially when the whole movie, and the last couple decades of his life was dedicated to having a family with his collage pic, that he simply tosses out the car window.. Not to mention Leo was built up to be such a bad ass, and Cann takes out his whole empire in about 5mins..
Who said he gave up his family just for his partner? Frank's decision to erase what he'd created and go after Leo wasn't prompted solely by his desire for vengeance over his partner's death. That picture collage he chucks away seemed like a ridiculous fantasy to him at that point, being that the worst case scenario happened. He now belonged to someone.
As for the "deep background friendship with his partner", the very fact that Frank invited him and his lady along for the celebratory day at the beach showed that there was brotherly love there. Besides, Frank's other partner (the silver-haired guy) wasn't there, so Belushi's inclusion in that scene served a purpose: To establish that he and Frank were friends.
And yeah, Frank does Leo's bunch in no time... but he gets blasted for his trouble. Frank got a bit lucky, but he also had that "attitude" he talked about in the beginning of the film (coffee shop scene), where he had achieved the "mental attitude" that he was a walking dead man. The circumstances at the end were different than on the prison yard years earlier, but the end result was the same.
If you've seen John Cassavetes' THE KILLING OF A CHINESE BOOKIE (a brilliant movie), you'll recognize where the bulk of the Frank vs. Leo scene was born from, both in terms of shot design and tonal execution.
Well the OP and somebody above mentioned he went nuts over his partners death.. Well I suppose it must have been that, because Willie dying had nothing to do with it. Well Mann sure made a big deal out of that collage pic, and then he casually tosses it.. It's funny after all the hardship he overcame in prison and his life, he'd let Leo bully him into giving up his life's dreams. Well ya they had a good bond going on vacation and working together, but Mann wrote in more of the Willie character.. So they rushed ending didn't add up for me at least, that Frank would be that weak just to quit his child and women, over just another problem he could solve like he has before.
Are you kidding? The whole damn story was heading in that direction. The end of the film was effectively -- even brilliantly -- set up near the beginning. ("I got to the point where nothing meant nothing. And I survive because I achieved that... mental... attitude.")
Unlike in Heat where De Niros character is set up the whole movie as a calculated, measured, disciplined, no-risk personality, then in the 3rd act completely goes against character for petty revenge to run unplanned into a hospital and leaving his girlfriend waiting in the car outside of the hospital till he messed around inside.
Jimmy Caan in Thief has serious anger issues, honestly he's a bit of a psychopath with some control over himself. He is measured but more of a risk taker than De Niro and will go that one step further, put himself out there if he feels wronged.
He told a story about to get what he wants or protect himself he will do anything, he gets into that emotional state where he just doesn't care if he lives or dies and through that he achieves the end goal.