Jerk with a Heart of Gold: Niki Lauda. He could have blamed Hunt for his accident at Nürburgring and the resulting burn scars. Instead, we get this exchange.
James Hunt: I feel responsible for what happened. Niki Lauda: Trust me. Watching you win those races while I was fighting for my life, you were equally responsible for getting me back in the car.
Also Jerk with a Heart of Gold: James Hunt. For all of his rivalry with Lauda, when a rude reporter asked Lauda if his wife could possibly still love him after the accident left him badly scarred, he tracked the reporter down and beat his face in for it.
James Hunt: Now go back to your wife and ask her how you look.
Niki placing 4th in the Italian GP, mere weeks after his nearly fatal crash and still healing from the burns and skin graphs, was awesome, but the outpouring of cheers and admiration from the whole crowd, including the other teams, was heartwarming all the way. Especially since it was all for the guy who people apparently didn't really "like".
Though Niki admits to not being the most emotional man around, his relationship with Marlene is heartwarming, especially when he drops out of the Japan race because he cares more about her than he does about a race that could get him killed.
Niki and James saluting each other before the last race.
Niki's small smile as he sees James winning the World Champion title at Fuji. Given that Niki smiles very rarely, that's a big deal, especially so because James has won the title from him. Niki obviously liked James much more than he let on.
Niki Lauda's Bittersweet Ending voiceover, particularly his final lines, regarding his relationship with Hunt:
Niki Lauda: People always think of us as rivals but he was among the very few I liked and even fewer that I respected. He remains the only person I envied.
Niki's marriage proposal to Marlene has to be the least romantic in history but it was adorkably cute.