Saeros insulted Túrin's mother and sister, causing him to throw a goblet at him, breaking the Elf's mouth. His response? Ambushing Túrin and trying to kill him. When he hears what happened Thingol pardons Túrin.
Androg and Forweg attempted to rape a woman in the woods for starters. Androg later killed Mîm's son with an arrow. It becomes quite clear why Túrin was ashamed and angered by the Outlaw's behaviour.
Túrin's murder of Brandir marks the point of no return for him.
When Gwindor returns to Nargothrond with Túrin, he has learned some things about Morgoth during his thralldom in Angband, and has the wisdom to see that Nargothrond must remain hidden and wait in hope for the Valar to deliver Beleriand. Unfortunately for poor Gwindor, he's now bent over, crippled, traumatized, and decidedly non-Badass, so everybody ignores his words. Even when Ulmo's messengers tell Orodreth point-blank that Gwindor's right, the king still takes Túrin's advice and goes to open war. It's only compounded by the fact that, typically, people who "escape" Morgoth return home as little more than his slaves or mouthpieces.
Brandir. He's a wise leader and a healer but due to his lameness is overshadowed by Túrin to the point Dorlas' mocks him to his face. Little wonder he becomes bitter.
Everybody, but Túrin, Niënor, and Húrin himself qualify most.
Mîm the Petty-Dwarf as well. His hatred and betrayal were completely justified after Andróg killed his son.
Poor Gwindor had to watch his brother being horribly dismembered, then he was enslaved and repeatedly tortured in Angband for 17 years. When he finally escapes he's maimed and traumatized, and when he manages to walk all the way home his fiancée falls in love with Túrin, his whole country decides he's too non-badass to respect him any more, and then the kingdom is destroyed.