FAILURE IS NOT AN OPTION.

Yes they're included in the festival date and both are happier to have Kris there with them, but they're still the third wheel. Because all the festival activities are designed for two people, depending on what the player chooses Kris very well might just have to watch Susie and Noelle do all the fun stuff while they stand aside. Even if they do get to do some of the activities, at the end Susie and Noelle still have their whole moment at the lake while Kris pretends(?) to sleep on the bench.

And then at the end of the chapter Susie talks about how their special thing, their thing thats better when it's just the two of them, now also has to be her new girlfriends thing. Sure, she has good reason to bring Noelle back on the team. Things are getting really serious, Noelle has experience in dark worlds and has powerful magic, and she's closely related to Carol and therefore at least one shelter code.

Still, based on the way Kris looks after that whole interaction, it's clear that no matter the reasoning, it still feels like their friendship with Susie being sidelined for her new romance with Noelle.

Then there's the new relationship between Toriel and sans. Again, I mean NO shade to these characters. If Toriel wants to experiment with the new guy she likes, she's an adult, and is allowed to do so. If sans wants to bang your mother, thats his problem. This is especially apparent with the added context from chapter 5. Toriel did not lock her kid out of the house, and she did not neglect her child for a man. Kris knows where the spare key is and could have let themself in if not for the plan to go to the church. Toriel knew Kris was out hanging with their new friend as they had been doing for the past few days, and trusted them to be safe.

However, even with all of that context, coming home with your friend after a long day where you both(?) thought your mother could be in danger (it's unclear whether Kris actually knew if Toriel was in the dark world or not) only to find her drunk and dancing with the convenience store guy would be upsetting for anyone.

Then after Kris said they were going to bed, Toriel and sans continued to be loud and disruptive and keeping them from falling asleep, prioritising having fun with each other and disregarding Kris's comfort.

Finally for a good rule of three, there's the relationship between Dess and Asriel. Theres a little less evidence here, but based on the love letters Asriel had for Dess and what pizzapants said about them "practicing" on each other, aka kissing probably, there was something at the very least vaguely romantic going on. Romance that was taking priority over their friendships with Kris, as demonstrated by the fact that Asriel and Dess were practicing kissing instead of practicing their band with Kris, specifically during times they had most likely set aside specifically for band practice due to pizzapants also being there.

This recurring theme of the romances surrounding Kris being seemingly more important than their platonic relationships with those people feels very reminiscent of the aromantic experience, with how people act like romance and partners are inherently more important than friendship, and how because of that aromantic people often feel left behind when their friends and other people they're close to "inevitably" start dating someone.