It's been a couple of years since I've seen DS9 now, but I can only think of three really bad episodes
2) The Muse
3) Profit and Lace
The rest of the episodes are watchable (and of course enjoyable, some more than others though
, but these three are absolutely horrible and should never have been made )
Just thought of another bad episode!
* "Let He Who Is Without Sin
So that makes it four really bad episodes