"Oh, you *ARE* sick..." --Eraserhead
I would have to agree with the Original Poster on this one, though I'd like to add the following.
First, I like (and even have a copy of) "Gummo". Upon careful viewing, it does, admittedly, provoke the desire to slip into a warm bath & open some veins, as watching the Failures Of Humanity (to steal a phrase from SA) on-screen, all the while knowing that you, at least biologically speaking, are in the same Genus as those perpetrating the actions you're watching -- and therefore virtually genetically identical -- does tend to drive people into self-immolation, or even psychotherapy.
Second, DO NOT assume you're going to watch it just once...Be prepared (provided you survived the initial viewing w/o reflexively trying to chew through your own wrists) to watch it MORE THAN ONCE, as -- after you've damaged your own brain thusly, the temptation to MAKE OTHERS WATCH IT can, at times, be difficult to resist.
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Seriously, though -- all joking aside -- it really is not the most horrific/bizarre/soul-destroyingly banal movie I've ever seen...Not by a stretch, sad to say...Although just remembering the scene with the kid wearing the fireman hat & boots while whipping the ___ in the tree is enough to bring back warm, Gummo memories (...), and in fact, that particular scene alone would make for a good vidcap-turned-desktop-wallpaper, IMNSHO. Utterly fantastic. Just fantastic.
Hobbes would probably have given up writing Leviathan (or at least revised his already somewhat dim views on the nature of man to more accurately reflect the much darker view shown in that particular flick) had that movie been available in his lifetime. Curse the luck.
~JMB