I helped a man, who was attacked by ghouls. He was transporting a wagon full of corpses, which draw the ghouls to him. He told me that he needs the corpses for living ( he probably sells them to relatives) I got the choice to either destroy the corpses or let him be.
I decided to not burn the corpses.Velen is a poor place and I wouldn't want to destroy a man's only income. I feared that I would found him later killed by ghouls but the consequence was even worse.
Later I met him again. He got sick, his whole face was covered in red blisters. Apparently the corpses infected him with somekind of disease and he begged me to kill him. I did. Judging by his look I was sure nobody could help him. I thought I would release him from his pain but couldn't get rid of the feeling I f****** up in the first place. I felt really bad afterwards.