Throughout highschool and college I knew a decent amount of people who experimented with drugs. But only a few who injected heroin, and all of them expressed that they weren't sure they were ever going to be happy again without heroin. And now most(maybe all) of them are dead.

I'm sure that's not true of every user, but enough of them that I really think heroin(and strong opioids in general) is a different beast.