This is one of the things I tend to get annoyed at over shoujo manga (though, it's not the only offending genre):
> Girl and guy into major fight over something pretty big (e.g. the guy admitting he just plays around in this manga)
> Girl hears sad story of guy totally unrelated to the reason they fought
> OMG that thing I was super angry at earlier suddenly is no longer relevant!!
> They get back together
Of all the off-beat "logic" manga and anime throw at me, this is the one that pisses me off the most for some reason :/