I can name at least 3 things that I'm mentally allergic to. I am limiting this list to non-living entities because if I start ranting and raving about types of people (and okay, movies) I'm allergic to, I might get stoned to death, so let us not go there.... for now.
The first two objects are actually foodstuff. My mental allergy stemmed from the following elements -- food that I actually ate when I was very young (between 5-6 years old), situation that involved sickness (fever, malaise-stuff that kids go through..) and a physical reaction moments after eating the blasted thing. Am trying not to be graphic here so I hope you get the drift.
One of them was chico (the fruit, also called Saponilla, thanks to Google). I recall crying my lungs out after the horror of it all. After that episode, I swear that I can never, ever, ever, ever look, and moreso, attempt to taste the poor fruit. Until this very day. I cringe when I see it. Unless you really hate me, don't bring this near me ever.
The other one was the apple pie. The boxed variety that was introduced in early 80s via a rising foreign fast food joint. My father bought it as a pasalubong one weekend. Never tried it again (I am omitting the details). It took years and years before I overcome the anxiety of having to get gastronomically acquianted again with any apple pie. I made peace with the said apple pie but I prefer the traditonally baked ones.
Mental allergy is mostly a state of mind rather than an actual physiological reaction. It involves anxiety, palpitation, stress, name it. Probably the same feelings induced when you are actually in love but in this case, you happen to hate it. And because the brain is quite powerful, the mental impact is strong enough to obliterate reason. And just like the usual allergies, it does leave you with funny reactions, mentally speaking. If I do a reverse comparison, my mental allergy to those foods has the same strength (but in reverse) as the addiction of people young and old to the Twilight series.
I also grew up having physiological allergies. I am allergic to seafoods (shrimps and crabs were the worse) and I share this with a sibling as well. Unfortunately, my son inherited this allergy too. I was able to overcome this only after giving birth to two children. I don't know if those events are related but all I knew was that the allergy disappeared only after the second baby. Some never outgrow of the allergy so I consider myself lucky to be able to enjoy chili crab and cereal prawns now. I am also allergic to detergents but this did not excuse me from having to wash clothes or wash the dishes (pre-Joy dishwashing liquid era). I had to wear kitchen gloves. I also grew out of it later on which is a good thing considering I ended up working with detergents.
I did say I'm allergic to three things.
Lastly, I am (mentally) allergic to the sun. When we had our first ever beach outing, I stayed too long under the hot summer sun and ended up with sunburn. Not a good sight, believe me. And ugh! When the old skin started peeling off? Gross! I ended up looking like a dark ghost in photographs (I was vain). My natural color came back but I swore not to repeat this episode ever.
In my second year of high school (I spent one year in Siena College Taytay after moving from the city to the ultra suburbs), I had a morning class and I would arrive home by noon time. I don't have enough money to take the tricycle ride from the main highway to our home so I will have to walk for 500 meters or so. I carried an umbrella every single day. The non-folding variety, even though it was a nuisance. In my first year in college, I carried an umbrella as well (folding one) even though the university and my dormitory was literally next to each other.
So now, while I have kids who love the beach, you can only make me swim when it's overcast and close to sunset. Any photograph under the sun is a concession on my part (and I've slathered tons of sunblock prior to that). Given the amount of ultraviolet rays these days, you are out of your mind to actually desire sun exposure. And it is incredibly ageing. So nope.
The irony of life is that while my allergy to the sun is probably all in my mind, it ended up that my daughter who love the beach did have a real allergy against sun exposure.