I strongly disagree on accusing a storywriter of lazy writing just because they skipped over how the relationship came to be. By that logic, we'd have to ridicule every show, movie and video game that ever existed in which the epilogue involved a time-skip after which we see that some characters have paired off (sometimes even got married) simply because the writers didn't show us how those relationships came to be (pre-timeskip ship teasing doesn't count, I think), regardless of how well-written the rest of the story is.
Example: Yamato and Sora getting married in the epilogue of Digimon Adventure 02; while there was plenty of ship tease between them in both the first and second shows, we've never seen them actually dating each other by the time of 02's final battle, yet I have yet to ever hear anyone bringing that up as a point of criticism against the show.
"Our magic is not omnipotent. A little bit of courage is the true magic."
–Negi Springfield, Negima: Magister Negi Magi
"Where there is distress, therein lies a story. Where there is a story, therein lies a will. And wherever there is a will, therein lies a soul."
–Evangeline A.K. McDowell, Negima: Magister Negi Magi