Oft-repeated statements highlighting the similarities of horror and comedy in terms of their emotional requirements and polarizing nature aside—there is something they have in common. Something only someone who experiences them a lot would know, or, at least, would know intimately.
And that is the nature of becoming numb. Coffee, caffeine more precisely, is something the human body develops quickly an immunity toward. It might become possible for a single shot of espresso to not have much of an effect at all. Much is the same of comedy and horror.
You get really desensitized. Enough comedy routines and it takes a massive effort and show of skill to get a smile. Seen one dead body on the screen, one horrific monster, then twenty more, and you suddenly are difficult to scare.
I find this cycle of simply becoming unable to have a reaction to weak stimuli after a while is true of most things. I used to live in Chicago, and below zero temperatures became a weaker and weaker aspect of the frozen winter as I grew. Summers in Florida used to wipe me out and destroy me—now they are still a rather warm time, but not that big of a deal.
And, really, I do not know how one might take themselves back out of a spiral like this. The brain becomes strong even if something is alienating—and it can be alienating. I am not disturbed easily, and it makes it hard to remember what might be upsetting for another person.
The only advice I have, I suppose, for you that find an immunity to the weak forms of something and seek the more intense versions, is to find others like yourself. Because at least rest assured you are not the only one. There will always be someone out there who can handle an entire bottle of vodka without flinching or have no issue at all with being covered with bees for an extended period. And, for the sake of the sanity of both you and the people who are not quite at that tolerance level and stare in horror at the level of chili peppers you might swallow, it’s good to know who your comrades in hobbies or culture or skills are.