Its not the first time Jill has failed to consider another viewpoint. The Chad incident is another plot point for her. Like I said earlier, her defining character trait is that she believes whatever action she takes with her relationship w/Fuckface is the right one. Or at least comes from right place. Her solution to a friend being bullied is to tell someone and get help because that's what she would want done for her.As was mentioned, the problem is precisely that Jill can only see this incident from her own point of view. She knows how important this picnic is - that she's defying Tybalt's ultimatum to give the MC the only gift she can give him AND that this is the best chance to left him down easily now that she's been 'forced' break things off with him. But she never stops to consider that the MC doesn't know any of that because she's refused to tell him all week! She never stops to consider that from the MC's point of view, Sage's mild cold is still a more immediate crisis than an impromptu date. She never thinks about how she'd feel if the MC bailed on her while she was sick to go on a spur-of-the moment date with some other girl.
Is she flawed? Yes. What's the saying...."the road to hell is paved with good intentions"
DPC has established that she has an imperfect view of relationships through small reveals, such as the date with Rusty, the short backstory with her parents (her closest relationship is with her sister), the first date (she's not particularly close with her extended family and I suspect she's not altogther THAT close with her parents.
Chalk this one up to video game logic. DPC clearly isn't making some kind of Harem game so there has to definitive choices, even if their real world logic doesnt hold upAnd it's worth noting that the MC can tend to Sage even if he's not on her path. The basics of the Sage branch wouldn't really change if the MC had to tend to, say, Derek instead of Sage. So even the idea that Jill is jealous of Sage is, IMHO, fundamentally problematic because we know Jill's reaction doesn't actually hinge on the MC's actions. Jill is behaving like a paranoid girlfriend even as she refuses to tell the MC how important he is to her.
She doesnt see herself as self-centered. Quite literally the opposite in fact. She is consistently written this way and well within established parameters for her behavior.Once you see that, it's hard to ignore just how self-centered Jill is being here. Even if we accept that she's hopelessly naive rather than jealous, she still could have tried to reschedule with the MC once she had time to think things over. You'd think she'd *want* to give the MC another chance to prove himself (much as she rationalized a way to give him a first chance despite the ultimatum). But she never does. She goes from being borderline obsessed with the MC to writing him off for the rest of Season 2 (maybe more) in a single conversation.People rightly give Maya a lot of flak for her passivity, but Jill takes it to a whole new level.
In short, I dont see it as poor writing on DPC's part.
Agree with your thoughts on Sage though