While nothing in the SE will ever be worse than Han not shooting first, Han stepping over Jabba's tail is definately 2nd worse.
I think Jabba is worse. Besides looking awful, the dialogue is basically a repeat of what we just saw with Greedo. (for obvious reasons, since the Greedo scene was done as a replacement for that scene originally). Then you have the walk-over-tail bit which is an embarrassment for such a powerful gangster AND Han looks all wonky and digitized doing it. You have Han say "You're a wonderful human being" which makes no sense at all. Then, to top off the utter horror that was just witnessed, Lucas adds a cherry: Boba Fett gawking at the camera as if to say "I'll be back".
As a scene, it is a total disaster beyond what one would conceive if you wanted to sabotage Star Wars. It's genius for its idiocy.