The only rule of writing is don’t be boring.
Pretty much nothing else matters.
Reading is a leisure activity. Yes, reading can teach you life lessons and change your worldview, but the principle reason people read is because it’s an enjoyable thing to do.
And writing is a leisure activity too. This is all supposed to be fun.
Reading and writing can of course evoke a range of emotions, and this isn’t to say every story needs to be a comedy or a romp. But as you write, goal number one to which every other goal should be subjugated is to tell an entertaining story.
(This advice is optional. You don’t have to do it. You can write and read boring stories if you want and nobody can stop you.)