I think for me it's mostly based upon the premise, really. Jane the Virgin is a play on the telenovela; Crazy Ex-Girlfriend is a dramacomedic musical; but the Mindy Project always felt foremost like a romcom.

When the couples that were lead up to be possibly The Romantic Couples 'died', it didn't feel like a 'betrayal' (too harsh a word, but you catch my drift) for me in CXG and JTV because they were never the heart of the show (also, obviously both shows still have room for new romances)

But in The Mindy Project I thought I saw what they were going in the first episode; definitely by the season 1 finale; and when they turned Danny into such a jerk, it definitely had a part in me quitting the show; though it also was because I was simply starting to enjoy the show less overall.

So, basically, for me is: it's the romantic coupling at the heart of the show? Was it 'promised'? If so, if they don't end up together (or worse; end up together after it has been made clear that they don't work after continuous break up/make ups), I'm gonna be mad. If it's not the premise or the 'heart' of the show, I might be sad if I really love the coupling, but I'll still enjoy it.

Which...doesn't really answer the question, I guess :P but in the end, if the characters can end up together, happy, and not at the detriment of either of the characters I will always prefer that; but I enjoy both 'realistic' shows and 'idealistic' shows. As long as I don't feel lied to. (which doesn't necessarily mean that I was being lied to, tbf)