I don't mean the crappy episodes, e.g. "Shades of Gray," etc. I mean, which episodes which are generally well-regarded make you dislike this show?
For me, it's probably "Half a Life." Love the performances, even love the moral issue at the core, but ultimately, the episode ends up typifying the wishy-washy way Trek treated cultural differences. There's absolutely no good reason why Timicin should kill himself at the end of the episode, yet there he goes, and the episode seems to fall back on "well, that's just his culture!"
20 years on, a lot of things embarrass me when I watch TNG. First and foremost, it's this kind of weak and annoying moral stance that sticks with me.
If I weren't such a fan of DoS from his MASH run, I'd prolly point up this ep's flaws a little more. Like, why was apparently no knowledge on Starfleet's part that these people have this custom? And why are the other cultures in this and 'Suddenly Human' allowed to seem the injured party while the UFP is portrayed as strident? Picard wasn't trying to change the whole culture of either of these peoples, yet in both instances war parties were called and fleets raised to bring back one individual. Also, I'm sorry, the need for the ritual had long vanished. People who can try and fix a star can feed and care for a large population. I hope Lxwana started trouble for them the instant Timicin's celebration was done with. And wasn't the life of their SUN more important than almost anything? I know we hold certain things sacred and stubbornly, but if a solar apocalypse doesn't focus the mind, what will?
Back to 'Suddenly Human'. The signs that Jono's father was an abuser weren't just snooty elitist Humans assuming the worst about a war-like culture. The physical signs on Jono and the reasons offered up by his adoptive father were classic RL signs of abuse. If a teacher or counselor ignored them, they might be fired or worse. If they wanted to do an ep about Humans and assumptions, then they should have shown Jono with no signs of injury and Picard and crew just deciding that a peaceful culture was better. That was never their simple assumption. It may have been mixed in there, but think - if a parent said 'he falls down a lot' and 'likes to play hard with older children', wouldn't red flags go up? Jono's father was actually a good father and his de facto parent for all intents and purposes. But he had seized the boy under at least questionable circumstances, and repatriation had to be at least an option presented to Jono/Jeremiah. This wasn't Humans looking down at others. It was an awkward situation with bad information and residual mistrust from a war, coupled again with RL red flags for possible abuse.
I don't know how many fans 'The Cradle Will Fall' has, but the Aldeans infuriated me no end, and it seems they got off easy. A firm tongue lashing from Picard was needed, IMO, not just a firm glare when they realized he was right about the shields. And since the other kids were too young, I would have had Wes say what all kids know : The worst punishments await the kid who takes something after being told they can't have it, especially if it belonged to someone else. In general, TNG was too tolerant of 'desperate/dying' as a slate-cleaner for a people's actions. As a mitigator, sure. But too often it seemed a straight absolver.
Lastly, one I know to be a fave : The First Duty. Wes needed a downfall from his MS status, but the lessons were muddled IMO. Wes didn't do the right thing in the end-Picard was about to call him out, and no united front of cadets was going to survive the expert testimony of the crew that brought down the Borg. Also, Locarno, who had led the lying and implied defamation of a friend dead because of his leadership, somehow got to look good for keeping his word by accepting responsibility. Like Wes, he had no other choice. His bravado had him in a corner once the jig was up. I've heard it argued that this shows the ep's complexities, but as presented, Wes supposedly did the right thing and Locarno supposedly kept his word. At phaser-point, I find that not so impressive. Also, and this one is just me - I would have had a downfall ep for Wes involve not a hearing, which in almost all other ST is resolved in the character's favor, but one of his miracle solutions gone very wrong, and then him finding out a simple solution might have been the better choice, and guilting over it.