it fucks people because its the best feeling ever... like meth i guess
you feel so good that anything else is boring. Sex, chocolate, the pump all work by releasing certain neurotransmitters that make you feel good. Heroin does that 20 times stronger. The feeling is over whelming and people can never be content with a sober, normal life after.
You dont go from driving a merc to a hyundai without thinking about the merc everyday of your life... or from banging a 10/10 to a 6/10 like its nothing. That can help you relate how heroin is (or meth)