Quick note that mostly concerns modern consoles with multi-platform releases: I'm just listing the version I played. Just because I don't list Two Worlds for XBox 360 doesn't mean I think it's better than the game I listed, it just so happens I played the PC version.

NES - Final Fantasy 2
Now, that's not to say FF2 is a bad game. It's true I consider it one of the worst FF games, but it was still entertaining enough for me to not call it bad. I just haven't played that many NES RPGs.

SNES - The 7th Saga
Incidentally, this game was actually published (though not developed) by Enix. I'll admit I didn't play it that long (probably an hour), but in that time I saw enough to see I wouldn't like it. Combat just didn't feel right, enemies felt way too strong (which at the very start of a turn-based RPG is just a blatant sin) and well, I just couldn't find any redeeming factors.

SEGA Genesis - Phantasy Star 2
Granted, I've only played two RPGs for the Genesis: this and Phantasy Star 4. But where I loved 4, I just couldn't get into this one.

Gameboy - Final Fantasy Legend
Now, for you SaGa fans, don't worry, I won't bash this game or anything. I just couldn't get into it and the only other Gameboy RPG I've played was Pokemon, which devoured a lot of 11-year-old-me's time.

Gameboy Advance - Medabots (Metabee version)
A game in which a little boy gets his first robot and goes on a journey to collect all the robots, fighting other robot trainers and become robot champion. Now replace the word "robot" with "pokemon" and you'll see why I'm a little suspicious of this franchise that started less than two years after Pokemon. (This is not actually the first game in the franchise, just the first localized one)
Anyway, that aside (because I'm perfectly capable of enjoying unoriginal things), on paper, this would actually be perfect for me. I like the pokemon games, I like robots. Sadly, the gameplay left much to desire.

Gamecube - Tales of Symphonia
Now, with this one I need to make a distinction: This is my opinion *now*, rather than back during the Gamecube era. Tales of Symphonia has just aged incredibly badly (probably because it's the first 3D Tales game). This might be a bit unfair, so I'll also mention what my choice would have been otherwise: Baten Kaitos Origins, the prequel to Baten Kaitos. Anyway, all these games are actually still plenty enjoyable. Gamecube may not have had many RPGs, but of all the ones I've played, none were actually bad (no, I did not play Pokemon XD).

Playstation 1 - Vagrant Story
This is probably the entry that'll get me the most side-eye. I just did not enjoy Vagrant Story at all. I felt like the gameplay was a clunky and unintuitive mess. I can't judge the story because the gameplay stopped me from ever reaching a point where I felt like there was enough of a story to judge.

Playstation 2 - Orphen: Scion of Sorcery
Apparently based on an anime, although I had no idea at the time. All I know is I thought the combat was terrible, which was enough to stop me from even getting off the ship you start on.

Xbox 360 - The Elder Scrolls IV: Oblivion
Now, there may be a handful of mediocre JRPGs on the XBox 360 (such as Infinite Undiscovery), but I could still get into them more than I could get into Oblivion. Why? Well, I'm just not that into western open world RPGs. Also, the Elder Scrolls combat is utter garbage.

Wii - Pandora's Tower
The third and least known subject of Operation Rainfall. I don't know if I'd say it was actually a bad game, I just couldn't get into it and didn't see anything that made me think the game had promise. FFCC The Crystal Bearers was another contender here that I couldn't get into, but that one did show some promise.

Wii U - Tokyo Mirage Sessions #FE
Now don't get me wrong, overall it's not a bad game. The story and writing is pretty laughable but the combat's fun. It's just that the only contender here is Xenoblade X, and I love Xenoblade X.

Nintendo Switch - Tokyo Mirage Sessions #FE Encore
Because yes, I did in fact buy it again for another console. And it's still not a bad game despite the bad writing/story, but its contenders were still better.

Nintendo DS - Blue Dragon Plus
First off, I'll admit there's some bitter-ness mixed in here with what I actually think of the game itself. Of the two Xbox 360 RPGs Mistwalker had, it decided to completely abandon Lost Odyssey, which I loved, and expanded Blue Dragon, which I didn't like.
That aside though, taking a console RPG and making an RTS sequel to it on a handheld didn't work out too well for FFXII and it works out even worse for Blue Dragon.

Nintendo 3DS - Fire Emblem Fates
I'm one of the few people who disliked the direction Fire Emblem Awakening took the series. I can't quite pinpoint the problems I have with that direction, but regardless, Fates carried on in this direction and added a worse story on top of it. (Three Houses was more to my liking again, which is why that wasn't my Switch entry)

Playstation 3 - 3D Dot Game Heroes
Ideally, this wouldn't be my PS3 entry. The game itself would've been fine, BUT...the performance is terrible and the game just crashes all the damn time. The actual unplayability of this game pissed me off, and that's why it's on this list.

Playstation 4 - Secret of Mana Remake
Look, my heart has a soft spot for Secret of Mana. It's what got me into RPGs in the first place and I loved it. The thing is, the gameplay has issues that have aged very, very badly. The remake should've fixed those, but it didn't. The remake keeps the entire damn gameplay the same, including the many issues and including the aged feel of it, and that makes this a bad 2018 game. I don't have quite the hate-on for things the remake *did* change like other people do, though. I'm fine with either graphical style, and while I prefer the original version of most themes, I don't dislike the new versions of the various themes either.

PSP - Crimson Gem Saga
Not so much bad as just..supremely generic. It takes the most generic parts of the hundreds of RPGs out there and mashes them into one generic blob. It was just a boring game that didn't really try anything, which to me is worse than being a bad game that at least tries.

Playstation Vita - Tales of Hearts R
Not a bad game, really. The story premise is okay, and the gameplay is, well, Tales. Unfortunately for Tales of Hearts R, I love each and every single one of its contenders on the Vita.

PC - Risen 2
Honestly, with the long and varied history I have with PC RPGs, it's impossible to say which one I actually thought was the worst. But Risen 2 is the first that came to mind and is definitely up there. Again, I'm not really a fan of western open world RPGs, and then Risen 2 adds a lot of clunky and janky things on top of that.