Best is probably snorting a phat chunk instant release 40mg oxymorphone..soo pure.
Best smoke taste besides buds would be opium.
Worst is probably chewing up tramadol(like chomping a few in halfs or a bit more)just thinking of those days gives me a shiver that directly reminds me of the withdrawal.. .I'm sure there is other things that I would consider worse but idk for example: dxm tussin, poppy seed tea, kratom powder toss n wash, or whatever drug it may be of course was a task, a bit nauseating especially for first time kratom powder(inhaled on accident while on my tounge before I could chase it with something) are things that YEAH gave ya shiver or maybe dry heave BUT this "task" at hand became easier and you sort of become accustomed to the nasty taste and therefore does not bother much anymore...like dxm, chug it all done it's sort of similar to your worst shot of alcohol. You just get that shit down the hatch and that's that.
But chewing up tramadol will forever haunt my taste buds lol