The Fight, VOY 5
Truly, the best way to ensure than an episode stinks is to base it on Chakotay.
Even if it has cool stuff like “Chaotic Space” and aliens that attempt to communicate with you by subtly altering your DNA to predispose you to schizophrenia (and, hence, make you cuckoo bananas, but also receptive) this all gets flushed down the toilet when the camera is on Chakotay – the worst second-in-command ever.