Everyone's body reacts a bit differently to different substances, legislation should seek to inform people of the possible downsides rather than banning it completely because some people react poorly. This is well understood with other psychological pharmaceuticals, but with recreational drugs it is frequently overlooked.

Pot would definitely be second in my list. It's at the complete polar opposite of the addiction spectrum in my experience, and I had no physical symptoms beyond having a harder time falling asleep (incomparable to my experience with Kratom though) but the psychological addiction was the strongest out of all of them. Of course Kratom didn't cause any sort of substantial psychological addition in me, the feeling of warmth and general "feel goodness" I got from it was comparable and probably milder than a cup of coffee after having been off of it for a couple days, and subsided quite quickly after daily use.