Writing a depressed character.
I can't help but feel bad for him
I always feel bad when I have to play or write a depressed character . And they are always depressed because they have severe PTSD because our gamemaster for this year doesn't like it when we steal the spotlight from his pet NPC and kills half the party in a needlessly gruesome manner on a regular basis so that we have to rely on whatever last survivor of an ancient and glorious race/cult/clan/organisation he currently wants to imagine himself as.
I can't write sad characters because its either my empathy that drives me to tears or a welling feeling of when I re-read to edit, or that I can relate to whatever sad the character is having--regardless of my experience of it or not.
Heh, I know the feeling. Oddly enough, though, the "I can't write" problem for me is the opposite - I do better when my characters are upset for one reason or another. I guess it helps to have a reason to try to pull them out of that mire of misery and despair, something for them to look forwards to and press onwards towards. I can't write happy characters too well because they feel flat to me.
This is a common problem among many people, as far as I can tell, prevalent enought to birth the entire "true art is about suffering" misconception. My advice for when you are writing a happy character and cannot help but feel that he or she has no distinct personality is to try and do what I call "working from the extreme". This is a very common, very basic trick for creative distinctive ways in which your characters act and it consists of, essentially, exagerrating the character's traits and actions to a ridiculous degree while writing him or her so that you have a clear idea of their behaviour, and then toning it down to a believable level.
To illustrate:
John Lobb enters his kitchen. He is angry. What is his most extreme imaginable reaction to being angry in a kitchen? He is impulsive, so he grabs a sledgehammer and smashes the hell out of his stove. So now you have a good idea of what form his actions will take and can tone it down to merely opening and closing his cupboards very loudly and forcefully while searching for salt.
Or, Urist is in the food stockpile. What is the most extreme thing he can do? Hastily grab a fistful of food from every barrel, stuff himself until he cannot eat enymore and then
walk roll up to a booze barrel and spill it all over himself as he tries to pour it in his mouth. Tone it down a bit and you now understand that Urist occasionally overindulges and has a poor spatial awareness.