Why do we want a relationship ... then panic the second have one?

Why do we want a relationship ... then panic the second have one? Why is it that when we're single we can convince ourselves a relationship is exactly what we need, but the second we start getting close to someone, all we can think about is the little things we don't like and suddenly we start missing being alone. I've been thinking about this recently and I find myself in this situation all the time. I go on a few dates, I like a guy, things start progressing, then out of nowhere, I start noticing every tiny little annoyance about them, and I start terrifying myself with this imagined version of the future. Maybe he can't hold a deep conversation. Maybe he says the wrong thing when I'm upset. Maybe even just the way he walks gives me the ick. And before I know it, I've completely talked myself out of someone I genuinely liked. But why? On paper, they're exactly what I'm looking for and yes, they have imperfections, but so does everyone. And most people would just look past that, right? Not me. So I went down a little rabbit hole because surely that doesn't make any sense, but psychology suggests otherwise. The first part is that our brains are terrible at imagining what a future will actually feel like. Psychologists call this effective forecasting. They found that we're surprisingly bad at predicting how future events will make us feel. We often imagine they'll have a much bigger emotional impact than they actually do. Which explains why relationships in our heads often feel dramatically different to the actual relationship. When we're single, we imagine what a relationship will feel like. Someone to come home to, someone to travel with, someone to create memories with. We romanticize all of it in our minds. And then someone comes along and they have imperfections, and they're not exactly like we imagined, and the reality doesn't quite match the fantasy we already created. But here's the catch. We're not actually scared of commitment. We're grieving a version of our future that never actually existed. Some of us don't date the person standing in front of us. We're dating five years into the future. We ask ourselves, could I marry them? Could I live with them? Is this forever? You don't have to decide forever while you're still saying hello. Our brains are so good at imagining futures that don't already exist. How many relationships have ended before they've had the chance to begin? Which made me wonder, if we're always trying to predict the ending, are we ever really allowing ourselves to enjoy the beginning? I've started writing articles on Substack and if you go subscribe and check it out, I'm going to be writing lots of fun things.