I’m a strong believer in the value of 20 minutes of time. Between work, the anime I do watch, the fact that I do play games on occasion, and my ongoing quest to find the next To Heart*, I’ve got plenty of venues to bank my time. There’s no real reason to keep watching a show, even if I’m enjoying it a little, if it doesn’t have at least an upside of being an 8/10 product. What follows is a list of Summer 2013 shows I dropped more or less because of their lack of realistic upside.
*Parentheses include the last full episode of a show I watched before dropping it.
Symphogear G (Episode 2)
-2 episodes is really more than it should have taken me to remember how much of a garbage fire Aoi Yuuki’s singing voice was in this show. It’s a huge waste of Nana Mizuki.
Prismer Illya (Episode 2)
-The majority of the jokes in this one were legit funny. The problem was that there was too big a gap between each to make the show really engaging.
Sunday Without God (Episode 2)
-This show had an interesting world premise, but was far too caught up in teasing its custom set of proper nouns to go into the type of character building that would have made it actually attention-grabbing.
Blood Lad (Episode 4)
-It wasn’t that Blood Lad was explicitly unfunny so much as its humor just felt like it came from a can. Its style of comedy was occasionally amusing but ultimately monotonous.
Kiniro Mosaic (Episode 5)
-After its beautiful, well-researched first episode, the series didn’t lose its charm entirely. Still, it didn’t feel dynamic enough to hold my attention consistently.
C3-bu (Episode 7)
-Apparently airsoft players snipe at each other before tournaments on their days off? And successfully injure people? That scene was the guillotine on a series I already had pegged for death by a thousand melodramatic cuts.
Uchoten Kazoku (Episode 8)
-The more learned about the death of Yasaburou’s father, the less plausible it seemed. I also couldn’t keep watching a series where the guys eating the meat of animals they knew to be sentient were getting off scott-free. Even if they were getting punished at some indeterminate point in the future, it made me feel sick.
Kanetsugu to Keiji (Episode 8)
-As time went on, this series transitioned from a poor man’s Lone Wolf and Cub to a poor man’s Mito Komon. Big difference there.
*To wit, a school life romance from the golden age of late night that turns out exponentially better than any expectations I had. The latest candidate is Sentimental Journey, the series about 12 girls whose relationships didn’t quite work out that brought Kazuyoshi Katayama (who soon after directed Big O) back to TV after a 10-year drought.
Animetics 
Agree wholeheartedly Sunday Without God, Blood Lad, and Kiniro Mosaic. … And I never even watched the first episode of anything else you listed in this post, so I suppose I’m with you there as well by default.
Don’t regret rolling the dice on any of them, but there is a full series worth of time that did go into these at the end of the day. You probably dodged a bullet for the most part.
Illya: I’ve actually enjoyed this a bit more than I expected (mostly since this is the first Fate series I’ve committed myself to watching. I’m doing this wrong aren’t I?)
Sunday Without God: Yeah, it’s not the most memorable show out there. It’s not going to rate highly, unless it’s last few episodes impress me enough.
Blood Lad: I actually did like it for a bit in the middle, but yeah…didn’t exactly finish all too well. It’s ok, but nothing special.
Kiniro: Dropped after 3 eps.
C3-Bu: I could only manage to survive 2 episodes. I didn’t think it was possible for a series to tax me while watching it, and yet this show did.
Uchouten: Still plan on watching this series marathon style since it has been praised by a good amount of people, but I’ll probably be cautious since a few people I follow had some issues. Will see…
Gifu Dodou: Don’t know how you managed to last that long. Tapped out after 3 eps!
So
I think Fate series taste varies a lot by person. I couldn’t sit through one episode of Night but couldn’t pull myself away from Zero (though I nearly dropped it after the agonizingly slow beginning). If you want to watch the characters from that series parody themselves some more before it gets a second season, you might try Carnival Phantasm: http://www.youtube.com/watch?v=nPZtehFkRQs
With Kanetsugu to Keiji, I’m a big fan of bushido/yakuza-themed stories as long as they don’t get too nationalistic and xenophobic. Lone Wolf and Cub and Tenna Toori Kaidanji are two of my top 10 manga for that reason. The show started out as a pretty decent entry into the genre, and then got intricately political/historical with a plot that was way too convoluted in episode 7 or so. I can enjoy that type of thing, but it wasn’t what that show was good at.
That and Uchoten (because maybe the Friday Fellows do get theirs, maybe) are the two I see myself maybe coming back and finishing from this season. I typically come back to 2-3 series from a year later. The only thing from Spring I see myself finishing that I didn’t already watch are Mushibugyou and Hataraku Maou-sama, and I watched everything I wanted from Winter. It won’t be happening soon, though, because Fall has (among other thing) multiple KMA-winning sports series on the block.