Fans of the long-running fantasy drama Supernatural will be happy to hear a prequel to the series, entitled The Winchesters, is currently in production. The story follows John and Mary, the parents of Sam and Dean Winchester. The Winchester family is nothing short of dysfunctional, having been plagued by plenty of calamities.
Both the Winchester brothers have led extremely difficult lives. They have literally faced their nightmares time and time again. Even though Sam had Dean to shield him from hardships, he still got his fair share of misfortunes and many of those were even caused by Dean himself.
Jessica's Death
Jessica was Sam's girlfriend who died in Supernatural's pilot episode in the same manner as his mother. Even though Mary died when Sam was very young, her impact on his life is seen through the seasons.
After many more romances, Jessica is still one of Sam's biggest loves in life. He loved her a lot and her death broke him, at least for a year. It made him hell-bent on revenge, but more than that it affected him emotionally his entire life. He hallucinates about her and mentions her name throughout the show.
Tortured By Lady Bevell
Season 12 started with Sam being tortured by Lady Bevell, a member of the British Men of Letters. Lady Bevell is adamant about interrogating Sam for the crimes he has committed and as a human, she doesn't leave any stone unturned in torturing him.
During the torture, Sam plays things off, declaring that he has gone through much worse. Undoubtedly, he has, but being tortured like that couldn't have been a walk in the park.
Losing His Soul
When Castiel rescues Sam from Hell, Sam's soul is left behind. Thus, who comes back is not really Sam, but his soulless version who is cold and heartless. This soulless version of Sam was the opposite of the kind and feeling Sam fans have known from the beginning of the show.
He commits some extremely evil acts that regular Sam would never do. He lets Dean become a vampire, uses an innocent human as bait for Arachne (a spider-like monster), and even tries to kill Bobby. The result is that when he finally gets his soul back, he is cursed with the guilt of all his vile crimes.
Dean Going Dark With Mark Of Cain
Sam may not show it a lot, but he loves his brother almost as much as Dean loves him. Thus, seeing Dean slowly transform into a ruthless unthinking killer due to the Mark of Cain must have been incredibly rough for him.
After he gets the Mark of Cain, Dean started going dark slowly and he began killing even humans without as much second thought. Sam had to see his brother lose his humanity and for the Winchester brothers who hunt monsters, this is a fate even worse than death.
Mary's Death
Sam's life had been increasingly tough, but it all started when he was just an infant. His mother, Mary, was killed by the yellow-eyed demon when she came to check on him in his nursery. This event changed the course of Sam's life.
It can be said that every bad thing that Sam has gone through is indirectly a consequence of Mary's death. Sam's father couldn't deal with his wife's death and revenge consumed him so much, that he became a hunter and also made his kids grow up in the harsh hunting life. If Mary hadn't died, Sam probably would have had a normal childhood with his family, devoid of monsters and hunting.
Difficult Childhood
As a result of his mother's death, Sam's rough childhood is a major reason for how his life turned out to be. After Mary died, Sam and Dean's father completely neglected his fatherly duties and became obsessed with hunting the yellow-eyed demon.
It affected both the brothers negatively, but it was Sam who tried to outright rebel against the kind of life their father wanted them to lead. As a kid, Sam was left alone multiple times while John took Dean hunting with him. They would hardly ever have normal meals because they didn't have enough money and Sam had to give up his chance of a normal childhood or adolescence plenty of times because of hunting.
Cas Breaking His Wall
At the end of season 6, Castiel has a villainous arc as he colludes with Crowley in wanting to open the gates of Purgatory. When the brothers try to stop him, he breaks Sam's wall to divert their attention away from him. This meant that Sam will what happened to him in Hell.
It proves to be a much bigger trauma than the brothers could have anticipated. Sam's mental health starts declining and he has a hard time distinguishing between what's real and not. As season 7 progresses, his hallucinations get worse, and eventually, it gets too much for him to function normally.
Being Possessed By Gadreel
In season 9, when Sam was about to die, Dean lets an angel, Gadreel, possess him and he tricks Sam into agreeing to it. This is Dean's worst betrayal of Sam because it was non-consensual.
In itself, the act was a violation but more than that, Sam feels hurt because it was his brother who did this to him, whom he trusts the most. When Gadreel was in Sam's body, he killed Kevin, which made Sam feel even worse later because the act was done by his own hands.
Dean's Death
Dean Winchester died in the series finale, which is probably one of the most controversial deaths in Supernatural history. Whatever may be the fans' opinions of it, there is no doubt that Sam had a hard time dealing with Dean's death and out of all the people he has lost, this one hurt the most.
The brothers were very much dependent on each other and losing his brother after they were finally free from Chuck was really difficult for him. After his death, Sam is seen wandering the halls of the bunker alone, looking grief-stricken and he leaves hunting because he couldn't go on without his brother.
Soul Trapped In Lucifer's Cage
When his soul was trapped in Lucifer's cage for over a year has to be the worst thing that ever happened to Sam Winchester. His soul was tortured brutally by Lucifer. There is no concrete explanation in the show about what exactly happened to him there.
However, seeing the way he mentally spiraled after his wall was broken and hallucinated grotesque images (like flesh hanging from chains), it can be ascertained that he went through unspeakable horrors in Hell.