User blog comment:Thetwindler/Dropped/Discarded Ideas throughout the seasons/@comment-2605:A000:122A:408A:91E8:8778:19BB:9B0B-20191214224113/@comment-108.36.76.116-20191217190948

I think they did do a parrallel to Sam's bloods addiction, with the Mark of Cain and killing.

If Dean didn't do what he does, and led a normal life, he'd have to take up a dangerous occupation, cop, firefighter,  soldier etc., and take up a hobby like BASE jumping in a flying squirrel suit. ADRENILINE JUNKIE. Remember that time, when Dean thought Cass was dead. He thought he saw Castiel, while driving. Sam almost said Dean looked like he saw a ghost, "But you'd probably be jazzed."