There's a lot of seedy darker stuff beneath the surface. As a kid, I didn't stop to think what "spice" was, and why Han was in so much trouble for dumping a shipment to avoid being caught, but it's pretty obvious it's drugs of some kind.
Watching Jedi as an adult, it really seems to me Jabba is stoned out of his mind most of the time, as are most of his minions. (That doesn't make them any less of a threat though.) The palace throne room has elements of an opium den to it, not to mention it's suited for other sordid goings on.
Even the Ewoks have a dark element that's underplayed. They were going to cook everyone to appease their new golden god! A pile of discarded Biker scout armor in a corner would have been funny and dark, but Lucas didn't want to go there.
As Carrie has said the metal bikini was George's idea, what else came straight out of his twisted mind? ;)