The lack of respect for personal space is the worst. For example, if a roommate constantly barges into your room without knocking or uses your personal items without permission.
When your roommate has extremely different living habits that they are not willing to adjust at all. Say, you are a clean freak and your roommate is a messy person who doesn't care about hygiene. The constant struggle to keep the place clean and the arguments that follow can be the worst part of the whole roommate horror story.
Trust issues can be the most horrible part. Like when you suspect your roommate of stealing from you, but you don't have proof. You start to feel uneasy around them and can't relax in your own home. It's a really bad feeling. You might start to lock up all your things, and it creates a very tense atmosphere. This can make living together unbearable in the long run.
A horror story could involve a roommate who steals. I knew someone whose roommate took small things like money from their wallet or borrowed clothes without asking and never returned them. It created a lot of tension and mistrust in the room. Eventually, it led to a big fight and one of them had to move out.
The broken trust. Once you find out someone has cheated, it's hard to trust them or anyone else again in the same way.
I knew someone whose roommate was extremely noisy at night. They would play loud music or have friends over late, not caring that others were trying to sleep. The person tried to talk to the roommate about it, but the roommate was very rude and said they could do whatever they wanted in their own place. This made the living situation unbearable for the other roommate.
Maybe the roommate was a slob. Like not taking showers often, leaving the bathroom in a horrible state. Just gross.
No, it's not a true story. It's likely fictionalized for entertainment purposes.
My worst roommate horror story involves a roommate who had a pet without permission. The pet made a mess all over the place, chewed on furniture, and was not properly trained. The other roommates were allergic to the pet, but the roommate with the pet didn't care and refused to get rid of it or keep it in control.
In my experience, the most horrible part of jury duty was the nature of the case. I had to listen to really tragic and disturbing details. It haunted me for a long time after the trial was over. I couldn't get those images and stories out of my head.
The worst part could be the disruption of peace. For example, if you are in a quiet place like a library garden, and suddenly the quadcopter noise invades. It shatters the calmness and tranquility that you were enjoying.
Allergic reactions are the worst. When your eyes swell up and become itchy and red, it's not only painful but also a health risk. It can also be really inconvenient as you need to seek medical help, take medications, and you can't just ignore it. Plus, it means you have wasted your money on the lash extensions that you can't even keep on your eyes.
The worst part could be feeling completely alone and lost. Like when you're new and no one seems to care or help you. It's a horrible feeling in a strange new environment.