Apparently Zak S. added more to the RPGaDAY questions, because you can do that. My answers wound up way more '90s than I expected.
1. Worst game you ever played
Furry Pirates. Quite possibly the trifecta: worst rules, worst setting, worst experience.
2. Interesting rule embedded within otherwise baleful game
The spell-creation system in the Dragonlance SAGA game (the one with cards) was clever, although we never did too much with it.
3. Game you never played but you knew it sucked just looking at it
Street Fighter: the Storytelling Game.
4. Game you most wish didn't suck
Rifts. It has heaps of concepts that I love, but both the setting execution and the system are pretty much botched.
5. Game about which you have the most mixed feelings
Changeling: the Dreaming. I don't like the White Wolf "feel" (although it appealed to me in college) or the system at all. There were ideas in Changeling I really liked, although the central core idea (resisting Banality) did not work at all. I ran a lot of sessions, and it did click for a couple of games, but wasn't sustainable. It was a half-baked modern fantasy RPG that only worked if you turned your head and squinted just so. But the parts that worked, did work.
6. Old game most in need of an upgrade
Over the Edge is old enough to drink, and definitely shows its '90s conspiracy roots. A version that looks more like the modern world would be welcome.
7. Game you can run with the least prep
OD&D (easier if it's '74 OD&D and I can just grab a map and run).
8. Game with awful art (and who you wish you could hire to fix that)
Original D&D. I'd hire James Raggi to produce a single-book edited version in a hardcover with art and layout roughly matching that of Isle of the Unknown.
9. Best houserule you've seen in action and now use in your own games.
I don't really have anything for this, because I don't go about grabbing house rules.
10. Game you've most changed your thoughts/feelings about
5e D&D. I was all primed for hating it but then I went and played it.
11. Game you'd use to run just about any setting if you had to
Basic Roleplaying. Either Call of Cthulhu or the big gold book.
12. Game that haunts you and you're not sure why
There are three concept-heavy RPGs from the late '90s that I always wish I'd gotten a campaign together for when I was in college: Blue Planet, Fading Suns and Tribe 8.
13. Game that would probably be most fun to play a bee in
Over the Edge. Since it doesn't differentiate who gets what dice, you could totally have your sting as a combat skill for 3 or 4 dice.
14. Best Star Wars game?
The only Star Wars game I've spent any time playing is the one from Wizards of the Coast in the early 2000s. The only one on my shelf is the West End Games one, which I've always sort of "meant" to play but never have time to. So ... (punt)
15. Game that's good in theory but you're kind of on the fence about it to be honest
Dungeon Crawl Classics RPG. Has a ton of stuff I'd like, and I particularly enjoy the zine output, but there are a lot of things that hold me back from running it. The crazy dice and different stats I'm fine with; I can even get along with the streamlined d20 system it uses. But the magic system seems like it just wants to take over the game, and make it "about" wizards as if they weren't already big enough in D&D. I also think its appeal is primarily to gamers about 5-15 years older than me; namely people who were 12 in the period of the Holmes, Moldvay or Mentzer Basic sets, who switched to first edition AD&D. There is an element of nostalgia that I don't have, and am not quite comfortable with.