Lasting, crippling weaknesses inflicted on my character that never, ever get better and in no way could be construed as a strength.
Every other yahoo here has some lamesauce weakness like "hurr I fight too hard for my friends" or "durr I focus really hard on being good". These are not weaknesses. Being a Sith with a temper is not a decent weakness. Being a Jedi who can't understand love is not a weakness. Being a greedy smuggler is not a weakness. Being the last of your sparkling-special warrior race/clone batch is not a weakness.
I made a Jedi of the weakest things in the galaxy, have her crippling anxiety issues, then cut her arm off. Ghostlings get no bonus to balance being made of cotton candy, Aleidis will never recover from the years lost from her already short life due to stress, and losing her primary arm will always be a problem for her. Those are weaknesses.