Stefan has all of four big fears:1. Thalassophobia - Fear of deep bodies of water (So thanks for that Silas)
2. Claustrophobia - Fear of enclosed spaces (Again, thanks Silas, really appreciate it)
3. A loved one dying - (I could blame so many people for this)
4. His Ripper Side - (Thanks Lily, not for passing down the ripper gene cuz you technically can't control that, but for being such a wonderful mother -_-)
And not necessarily in that order
They didn't all stem from the obvious though:
His Thalassophobia was from when he was very young and was climbing a tree with Damon. The tree was almost directly over a lake and when Stef accidentally grabbed a rotten tree branch, well... you can guess what happened.
His claustrophobia was from when Giuseppe shoved him in a closet for hours after Stefan accidentally shattered a plate while Damon was at school and Damon had to eventually rescue him because Giuseppe forgot that his youngest song was literally in the smallest of closets without food or water and breathing through the smallest gaps in the walls.
His fear of a loved one dying was a given, I mean, who wouldn't be terrified if their close family or friends were in trouble (Emphasis on 'close' cough cough screw you Lillian and Giuseppe). When Damon was off at war, Stefan was perpetually terrified, especially when Damon wouldn't respond to his letters and Giuseppe would casually say that Damon was probably dead and Stefan wouldn't believe him but also wouldn't sleep for the next few nights.
And his ripper side was an obvious fear ever since he first discovered what he would do around human blood, but nothing terrified him more then when he almost broke free from Klaus's compulsion but Klaus threatened to let the Ripper loose in an elementary school full of children.
And that, ladies gents and nons, is why I hate Lillian and Giuseppe Salvatore. Thank you for coming to my Ted Talk.