I hated the way that the writers on Voyager ran out of ideas in the later seasons, and so started over-using the Holodeck. I mean, the whole point of doing Voyager, of having it be set far away from any area of space previously used in other series was so that they could do stories that just wouldn’t have worked if the rest of the Federation was nextdoor. But then what did we get? Show after show set entirely (or nearly entirely) on the Holodeck, hitting bottom with that insanely dumb Flash Gordon attempted spoof.
In all the series, but especially DS9, I hated, hated, hated all the inter-species romance and procreation! I mean, come on, how many people do you know who are sexually attracted to a gorilla or a chimpanzee? And yet we’re supposed to accept that Humans and Klingons and Vulcans and Ferengi not only get the hots for each other but can freely inter-breed? Just totally throws believability out the window.
I echo Domokun’s sentiment about the non-alien-looking “aliens”. It got to be such a total joke on Voyager; each week, a new alien species with a different pattern of bumps. How could their makeup people have such a total, complete, utter lack of any semblance of imagination?
Also add me to the list of people that totally hated Kira on DS9. Could not stand to watch or listen to her.
Lastly, I truly hate the “creative” people behind Enterprise. They had a good premise, and then wasted, wasted, wasted it by just rehashing old plots from TOS. In the beginning, they made such a big deal out of how this was going to be at the dawn of space travel, when everything was new and untested, blah, blah. Which could have been interesting, if they’d actually portrayed it that way! But just as I predicted from the start, they quickly got dependent on the transporters, introduced phasors with stun ability, used “hull plating” just like shields, had sensors that could detect whatever the plot called for, etc. What a waste, I’m extremely happy to see it cancelled.