Written by that prolific writer of usually hit film and TV productions Richard Curtis, this must be his idea of a Christmas stocking filler?
That is, it is light and airy and not to be taken too seriously, either plot wise or as a movie production. Its adequate, amusing, touching, and even laugh out loud funny in parts. Melissa McCarthy is its saving grace, delivering her lines with wit and charm, and emotion as only she can. The 3 actors comprising the family do not really gel together, the mum and daughter were not very well cast IMO. I think RC made the father lead watch a bunch of Stephen Merchant performances, and told him "act like that".
But it all held together well enough to enjoy as a pre Xmas movie taster, before you unwrap the real presents, such as Elf, National lampoon, A wonderful Life...or whichever are your go to Seasonal favourites.