I’m not entirely against framing devices when it comes to stories, but there has to be a good reason to include them. Point in case the Book of Life, which starts in the present with a group of school misfits on a museum trip getting a special lesson about an old mexican story that turns out to be the true core of the movie. An utterly generic setup concerning a bet between two gods of the underworld about whom of two boys a girl would marry when grown up, the aggressive action hero type or the sensitive musician.
It’s not that the movie is without charm, far from it, (I don’t think I’ve seen a major animated movie using Mexico folklore as a setting and with an art direction vaguely reminiscent of Mexican pop culture and with characters modelled after carved puppets) and once the hero enters the underworld it really gets good despite the unoriginal setup. But even after seeing the entire movie I still see no reason why they didn’t start with that story from the get-go and instead used an utterly pointless framing sequence that adds nothing other than a few minutes playtime.