Yoriko may be quirky (and unusually comfortable with beings of the Cthulhu Mythos), but the genuine affection she shows her son Mahiro is just plain adorable. The fact that she invented a silly excuse to hug him on a regular basis just makes it even cuter. Mahiro also deserves some mention here because despite the fact that he's obviously not a touchy-feely kind of guy, he willingly goes along with his mother's eccentric, snuggly ways, showing only mild embarassment when she glomps him during her first meeting with Nyarko and Kuuko.
Despite The Reveal being a silly moment, the Dating Sim episode has Yoriko pretending that her personality has changed to be even fluffier and somewhat ditzy, just so she has an excuse to dote on Mahiro even more than normal.
And on top of that, though we have yet to see Mr. Yasaka, it's very clear that Yoriko loves him with all her heart, and has loved him since they first met.
Zutto Be With You (Always Be With You), sung by Nyaruko herself. An upbeat, warm and sincere declaration of pure, romantic and idealized love that lasts forever.
Similarly, "Sister Friend Lover," sung by Kuuko, is a calm but cheerful melody, with Kuuko happily jumping through the background. The credits end with Kuuko kissing Nyaruko on the cheek.
Season 2, Episode 6. Nyaruko, who is very unhappy with Mahiro being so close to Kuuko, meets him in his room at night. Instead of trying to seduce him, (Which she has attempted before,) She instead bawls her eyes out while she goes on about Mahiro ignoring the fact that she really does love him, and how his refusal to just spit it out if he loves her back is driving her crazy. When Mahiro convinces her he doesn't hate her, she spends the rest of the night in his arms.
Pretty much any time Nyarko turns down her own "volume" and talks to Mahiro with genuine emotion rather than zaniness, you can expect one of these:
Season 1, episode 7. At the end of Mahiro and Nyarko's date, Mahiro is genuinely confused because Nyarko's been behaving well all day (well, mostly) and it looks like he's actually falling for her. Finally, he gets frustrated and says that the silly way she acts makes it hard for him to trust her confessions of love. Nyarko replies that she has a hard time expressing her feelings unless she's being silly, but promises that her feelings are for real, and she'll say it however many times it takes for him to realize this. Then she turns to him and says "Mahiro, I love you" while smiling sweetly.
Also, just before this, Nyarko points out that they got to do all the things she said wanted to do when she was hounding Mahiro - in other words, he gave her the perfect date, and she's thanking him for doing so.
Season 1, episode 8. Trapped in aDating Sim, Mahiro finds himself at Christmastime. While he's walking through the city, Nyarko runs up with her Christmas present for him...a marriage registration. Which he immediately rips up. But then Nyarko pulls out "Plan B", a scarf she hand-knitted for him, and actually makes him blush by saying it looks good on him.
At the end of the episode, Mahiro gets embarassed when Nyarko tells him that the only way for them to return to reality is for them to kiss, and starts to leave. Nyarko catches his arm and says "I love you" again while saying that this is the moment she's been trying to achieve in all the time they've been together, which is enough to convince Mahiro to go through with it.
Season 1, episode 12. At the end, everyone comes over to Mahiro's house for a barbecue. Nyarko notices that he looks pretty happy, and takes the opportunity to say "I love you" again. He's surprised, but she reminds him what she said before, how she'd keep telling him so he would know she was serious. Then she goes in for a kiss, everyone reacts, and that's how the first season closes out.
Season 2, episode 11. Mahiro and Nyarko discover that the chocolates Nyarko shared with the group during a camping trip were dosed with a Love Potion. When Mahiro asks if she did it on puropse, Nyarko swears she'd never do such a thing because while she does want Mahiro to love her, she wants it to be genuine love and not just something caused by a drug. When he asks why she didn't go nutty like the others, she responds that the feelings she already has for him are stronger than anything the love potion could ever cause.
Haiyore! Nyarko-san F, and this one doubles as a Tear Jerker. Nyarko has been infected by nanomachines that are slowly eating away her powers and memories. Towards the end of the OVA Nyarko is barely able to move, and has lost almost all of her memories. Mahiro is desperately trying to strike a Deal with the Devil to cure her, when Nyarko declares that she can't stand the thought of Mahiro becoming a criminal for her sake. She then tells him that it will be alright, because even without her memories, she will never stop loving Mahiro. Mahiro is so moved that he ends up giving her a Big Damn Kiss, which incidentally reverses the effects of the nanomachines.
In the last (aired) episode of Remember my Love(craft-sensei), Nyarko is preparing to go off and deal with the giant object that's landed on Earth, and is saying her goodbyes to Mahiro. Unable to hold back, she runs up and hugs him tightly, asking if they can stay like this for just a little while, and if she can do it again if she makes it back. In stark contrast to his usual Tsundere behavior, Mahiro is simply surprised at first, then smiles gently and says yes. Of course, it all turns out to be Nyarko over-dramatizing nothing, since what she was really doing was attending Space Comikket.