I was never particularly autistic about remembering anime, especially the ones I enjoyed less. I rewatch my favorites sometimes and it definitely helps but for some lesser known anime or OVAs is very difficult for me to remember. It's a mixture of convoluted storytelling and not being able to talk about it to anyone (memory is built on repetition) that makes it so I forget a lot about it besides key points or my favorite character's personality and traits. Having some internet friends or an imageboard will one hundred help if you're forgetful.
When I first got into monster of the week anime I used to keep track of episode quality on a small list, that way when I look back at the show after finishing it, I'd see how much I enjoyed or didn't enjoy it. It was annoying to keep track of all that shit so I eventually stopped. Ultimately, things like a shitty ending can ruin your enjoyment of a show even if you liked 90% of it, cause bad things stay in your mind for longer. That happened multiple times on me and I sometimes look back on episode lists and think to myself "yeah, that was worth the shitty ending"
I guess what I'm trying to say it that I think that even if you forget the show, you shouldn't forget how you felt about it. Even if you mix up memories and confuse a show with something else or forget the title or develop some fake memories on top of that, you should have faith in yourself and say "Yeah that anime… I forgot the entire second quarter but holy fuck was it hype!".
Don't blame your brain that you forgot anime plot points, and don't think that "I forgot this so it must be bad", if you've seen 100-200 anime you've got full rights to be forgetful. With that in mind it's not good to discuss anime like that, if you attempt to talk about a show you've seen 8 years ago online people will notice and call you a faggot.