I used to think that I hated people.
I remember this one trip I went on with a university choir I sang with in grad school. I was living in Utrecht, Netherlands, at the time. The choir traveled by train to Kiev, Ukraine, where we stayed in a kind of third-world hotel, and sang together with a choir there. In general, it was an intense, educational, and wonderful experience. We schlepped from the West to the East Berlin train station together. we arranged our backpacks in heaps on the the train to all sleep on. We shared food. We navigated Ukranian maps and signs together. We survived customs and frightening food and beautiful parks… together. We shared rooms at the hotel. I got really annoyed with people and gradually started to think that they were really obnoxious and insensitive. I hadn't been best friends with them, but we hung out and had fun getting a drink together after rehearsals. Now, on a trip that for most people seemed to cause bonding and deepen relationships, I thought they were all really pretty annoying.
In high school and college I lost a lot of friends to thinking they were obnoxious and insensitive. In reality, ok in ADHD reality, I see it differently; they may have in fact been obnoxious or insensitive, but no more or less than other people. What is more informative, is that I was tired. I was overstimulated. ADHD means I have no filters; when people are in my face I can't ignore what they're doing. When I'm overloaded with talk and laughter it feels like I'm two inches in front of a stadium concert speaker stack and someone is scratching a chalkboard with their fingernails on the other end of the mic. I can't turn off all the noise and information and faces and laughter coming in. The more tired I am, and the more intense the social contact, the worse it gets.
Nowadays, I'd say that I needed some downtime. I needed some time where I could control the noise I was hearing; where I could have a break from conversation; and that I might need a nap. And now I know that after that downtime, I might like those people again for a while. And any trip where I don't have any measure of control over that won't really be so much fun.