I said it before, but if Ootaki really wants to act jealous about Yakushimaru sharing her interests with other people, then he should just slap her face! You know, like how she did to him? /sarcasm
@BrunoVilla She literally asked the question, and the mother has a good point. For example, if I got a classic Volkswagen van and had wall-to-wall shag carpeting along with a waterbed, would that look good to you? If Yakushimaru was able to say "Yeah, these are in style now" or anything like that AND THEN the mother snapped back by saying something like they're out of style, THEN you would have a point.
Right now, the mother is being fairly reasonable. We literally see that Yakushimaru had NEVER even thought about modern trends and fashion, so that basically proves that the mom was right.