Too many folks take life too seriously.
They usually have such a high standard for most everything. They want things to be totally consistant to what they believe in and how the world should be. Anything wrong or different they react and in some, react too harshly which is not needed.
The world would be a better place if folks didn't take life too seriously. Yes you can take life seriously and such but not beyond a certain level that will make your stress level boil and create unnecessary havok upon others.
I don't know if it's their upbringing, their standards of living, the preprogramming of their minds, their development, fear, it could be a number of things.
We have a word for this, it actually a name people use when it comes to how people are when they become overly too serious. For women it call karen, for men it called richard.
And with it comes certain traits and personalities to go with the name. Basically know it alls, entitled, overthinkers, overreactors blamers.
If you want to spot folks who are just way too serious, just look for these folks. They always got to be right and usually create a performance to match their overdramatic personality.