I started using The Cosmopolitan Prayers more than 10 years ago as a metric to measure the lower limits of tolerably bad anime. Long-time readers will recognize the familiar invective, "WORSE THAN COSPRAYERS" which started out somewhat facetiously, but evolved to become a standard I've applied regularly where appropriate, albeit usually for shows I've quit watching. Through the first third or so of the current season, I'm somehow still watching the following three shows which fall below the Cosprayers Line of dubious quality: Masamune-kun no Revenge, Seiren, and Hand Shakers.
I don't have a good excuse to still be watching Masamune-kun no Revenge (Masamune's Revenge). I've read enough of the manga to know it will not develop into anything I actually enjoy, and the anime adaption seems to offer no improvement over the source material. The single best reason I can identify for continuing with this further is that Aki has most excellent hair.
Seiren manages to be a fairly serious disappointment even though I never had high expectations for it. Its Amagami SS predecessor also had numerous flaws, but I don't remember them being so irritating. Well, the Kaoru arc in Amagami SS+ Plus was infuriating, but for the most part the series was only mildly bad and managed a few good moments. Seiren, on the other hand, manages to give its male lead all the traditionally detestable characteristics stereotypically associated with Potato-kun. It's actually too aggravating to go into detail again, given I've already vented about him via IRC and the Twitter. I'm mystified anyone could watch the first four episodes and somehow root for this koala turd.
By now, Hand Shakers ought to be fairly infamous as being the winter 2017 train wreck of choice due to the sheer jaw-dropping horror of its visuals. But I feel it is also worth pointing out that Hand Shakers manages to be terrible in a lot of more conventional ways independent of its execution. In the interest of brevity, I'm just going to go ahead and characterize these failures as "straight-up stupid bullshit" and leave the negatives at that. On the other hand, I have to admit Tazuna is comporting himself remarkably well for an anime character considering he has to constantly hold hands with the mute carbon bag filled with water we're calling the show's heroine. He's a damn sight better than ol' Masamune or that marsupial fecal pap found in Seiren, that's for sure.