Stefan falls in love with Elena. Damon rocks up and tried to tear that happiness away by either killing her or by "stealing her" from him (his words).
Damon fucks up. Stefan ends up sacrificing himself to save Damon.
Stefan is with Klaus, a price he agreed to pay in order to save Damon. He's also trying to keep Klaus away from figuring out that Elena is still alive. Meanwhile, Damon is doing everything in his power to make Elena fall for him.
Elena and Stefan break up because she admits to having feelings for Damon. He's heartbroken, Damon admits to being gleeful. Stefan kidnapped, thrown in the ocean to die over and over again.
Still drowning. Eventually found, but brain fried. Soz bro
Downward spiral because he lost his brother. Pretty sure this is the season Enzo was obsessed with him.
Saves Damon from being killed by the Huntress, ends up marked and leaving his new gf to be on the run
Damon gets into shit. Gives up and forces Stefan to become a ripper to save the twins. Stefan makes ONE mistake and suddenly is the unforgivable villain. Sacrifices his life so that everyone else gets to be happy and after a few minutes no one even gave a shit.
That's his story y'all and I've left a lot of tragedy out. Fuck you writers for not giving happiness to the guy who's sacrificed the most (aside from Bon) over and over again.