Easy.....gadsby's in Sayerville, NJ. The whole place smelled like pee, even the parking lot.
And its West Coast equivlent, Club 88 in L.A (wonder if it's still around?), it definitely had that distinct aura of cat whiz for certain (yes, it was occupied by a number of kitties).
__________________
Never play slap bass for a bear, you'll make it VERY angry.
I don't know about the worst, but the Balinese room in Galveston sucks. If you're lucky enough to get a parking spot close by, it's a 600ft trek to the playing room from the curb on a pier built in the 40's extending over the Gulf of Mexico. Most of the time you're pushing or hauling your gear 1/4 mile along the crappy "seawall" before you even get there. I feel like any moment the floor could just go out.