this is a very personal thing, but i genuinely hated how mean they would get to each other sometimes, or the way they would refuse to communicate. any relationship has its ups and downs, but this one had way more downs than i would've liked seeing... maybe they were just fine for each other, but, while reading, i found myself really irritated with jonna while loving mari a lot. 
i loved the fact that it was different than an average love story, it was raw and so sweet and tender at times, more focused on the small things in life as a source of happiness rather than a flawless relationship with your partner. i think they can coexist, it just wasn't the case here i guess. lovely read regardless