There was one Star Trek movie which was so bad that watching it should be considered extreme punishment. That one was the “Save the Whales” movie. Absolutely the stupidest movie I have ever seen.I have totally hated the "save the whales" mentality, and the morons who embrace it, without reservation for decades.
In spite of that, this is my favorite ST movie and, if I understand correctly, world-wide the most successful of the series.
It was cleverly written, the humor was pervasive and, as entertainment, for me the best of the bunch.
God help me, that stupid save-the-whales one is one of my favorites. If only for the great chemistry, between Shatner and Nimoy, and Captain Kirk at his lecherous best coming on to Gillian, the pretty biologist. Gillian: "Don't tell me. You're from outer space, right?" Kirk: "No, I'm from Iowa. I work in outer space." It's a hoot, with great shots of San Francisco to boot.
On the other hand, even Star Trek at its worst (IMO, the molasses paced "Veeger" one) cannot hold a distant candle to the sheer torture of Jar Jar Binks.
I rest my case!