Well, most pictures of King Haakon tend to look like he could burn a hole straight through you with his eyes — but there are a handful where you see he was exactly as funny as Harald.
Maud is described from innumerable sources as being lively, energetic, multi-talented and with her own reserves of wit and humor, and I have no doubt she's the one who brought it out of her husband, as he had a pretty severe upbringing and was originally very quiet and lacking self-confidence.
Which is all to say — she smiled. There just aren't that many pictures of it. But there aren't many of ladies of that era grinning broadly. https://www.picuki.com/media/2508784337269468714
On the other hand, I have never seen a picture of her in such deep mourning (even Victoria was an evening event and didn't require the heavy veil and gloves). I think this must have been for her father. https://digitaltmuseum.no/0110143427.../media?slide=0