To be honest, I didn't really want to open a single chapter, but there are so many questions that I have to explain a few words.

Maybe it's because the previous statement wasn't clear.

First of all, learning magic in the HP world is not easy, and it is normal to learn a simple spell for a long time. (e.g. Harry learns the Flying Charm in Part 4)

So unless you have a strong X IQ for the whole world, there must be something to balance the difficulty of learning the spell.

If you know a spell and cast it with the wave of your wand, the young wizard only needs to attend a seven-day Latin memory camp instead of seven years at school.

This balance can be blue bars, spell slots, cast levels, cumbersome casting materials, and complex and obscure spells, but none of these "moods" fit in with the HP world.

After all, HP itself has spells that require emotions to cast.

The protagonist, as a time-traveler who has received decades of materialist education, has never had mood swings.

It's normal to not be able to accept the emotional setting of the wizarding world at first.

......

And then there's the Patronus Charm.

Patronus Charms are widely considered to be a form of advanced magic, far above the average wizard level.

When Remus-Lupin mentions this spell in Part 3, it is described as "particularly profound".

"That's very, very advanced magic...... that's how Hermione described Harry when she heard about Harry learning the Patronus Charm in Part 3.

When Harry Potter revealed in Part 5 that he (a fifth-year Hogwarts student) was able to summon a full Patronus, Amelia Bones (the second most powerful person in the Ministry of Magic, the head of the Law Enforcement Department, and a very powerful witch) showed great admiration.

The vast majority of witches and wizards are unable to summon Patronus in any form, and even invisible Patronus is seen as a sign of superior mana. Wizards who are able to summon a full Patronus are often promoted to the top positions of the Wizengamot and the Ministry of Magic. ...... Here's the description of Pottermore.

I posted so much of the above just for one sentence, that is, "The Patronus Charm is not something that can be used with a flick of a wand and a little memory!"

Dementors are violent law enforcement officers of the Ministry of Magic, so if they could learn to flip their spells casually, Azkaban would have become a playground.

To get back to the point, what the Patronus Charm needs is "truly happy memories".

What is true happiness, this thing may be a bit idealistic...... But it's certainly not that you want to have a memory of a cat and a dog, and you can feel happy yourself.

Moreover, as people grow older and become more mature, their "happiness" decreases.

When you were five years old, your mother would buy you a lollipop and you might lick it for half an hour, and when you were ten years old, you might be happy all day when she picked up a dollar on the side of the road...... Will you still be so happy when you encounter the same thing in your thirties?

At the age of thirty, even if you pick up a million on the street, you should think about how to hand it over to the police uncle in a hurry, instead of smirking and being happy.

Well, a bit of a stretch......

To put it simply, the protagonists are not without happy memories, but either too much time has passed, or they do not live up to the standard of "true happiness".

Above!