Opiates don't give everyone a feeling of pleasure. Having been into hospital and had "heroin" as a painkiller and then spent several days throwing up and feeling like crap despite anti sickness injections I can not see why people use it as a fun thing to do! I've just been in hospital again for an operation and avoided opiates as much as possible, but still had to have some and yet again ended up being sick (although I don't think the hospital food helped either!!) We all have different tolerances of drugs too, some like me are very sensitive to them, others need loads to get any effect, messing around with them is just way too dangerous.