Opioids have been found in comprehensive clinical testing to be among the safest recreational drugs available today, with no potential for addiction, no significant impairment of cognitive processes or motor skills, and no long term effects on mental or physical health other than making people like you more.
Sedation, but not sloppy like with alcohol or benzos
More enthusiasm, and an increased desire to socialize with other people (you'll actually have friends now!)
You'll start nodding off after a while
Makes such annoying shit as Lucky Star and YouTube Poopamusing tolerable. This is why you always see House watching shitty daytime soap operas and having a grand old time doing so.
And best of all, absolutely no negative side-effects. It's a wonder why more people in the world aren't popping, butt popping, snorting, smoking, and injecting these holy substances.