For me, it irritates because it's marketed as a feel good film that makes people feel warm and fuzzy at Christmas. So we have:
Colin Firth falling in love with a woman he can't talk to, and is seen having virtually no meaningful interaction with. He succeeds in proposing to her, although hilariously not before someone thinks he may have formed this bond with her FAT and UGLY sister.
Hugh Grant falls in love with (enormously fat) Martine so he fires her. Whatever nonsense ensues, we are left the ponder the obesity of Martine. Remember, loving a 'fat' woman is at best brave and at worst laughable to contemplate.
Laura Linney's character is left lonely because her love goes to her brother, who cannot offer her happiness in return.
Liam Neeson's stepson loses his mother. Dialogue between the two is dreadful, and both get over it all very quickly.
Egg from This Life is basically a stalker who makes KK's life uncomfortable. Would you really respond with a kiss in her position?
Tim and Stacey are dull. Naked but dull.
Kris Marshall and his women is funny in a surreal way. Bill Nighy has his moments. Neither are enough to make the film worth a second watch.
The only storyline that feels remotely real is Emma and Alan. And that's very sad.
So on my first viewing, as a younger person who had lost their mother in their teens, been cheated on, and was overweight and not happy about it, I didn't skip out of the cinema with a glow in my heart. And I still think most of the film is bollocks.
Why not approach anything you watch with critical faculties in action?
Come to that, why not wonder whether any woman Martine's size has watched this and stopped eating?
I get that lots of people love this film. That's down to them. I'm not stopping them. Just saying why I don't.