I remember playing "Thief: Deadly Shadows" a few years back (brilliant game, no matter what Croshaw says), and there was this one mission where - if you wanted to get 100% of the loot - you had to steal a bag of money from a young widow gone insane with grief over the loss of her husband (when you walk in the room where she's sitting in a chair she actually mistakes you for him and keeps babbling nonsense). The money was left to her by her husband and it was all she had to live on.
I took the loot, but to this very day when I think about it I feel so ashamed I want to kick myself in the nuts. Hard.