Slowly over decades, observing that no matter how hard I tried I would never be able to adjust socially and do what is obvious to other people. Trying to meet new people professionally, manage simple relationships at work, or maintain friendships even online are all impossible, let alone finding a partner. I try to be kind but I come off as an arrogant know it all. I try to help people but I'm too enthusiastic and spook them. I try to make the people I care about laugh, and not only am I not funny but I offend them. I have heard people talking about me behind my back more times than I can remember. To my face I'm always being told that I'm fine and it's all in my imagination, it's just self esteem and if I tried a little more I would be just fine.
Nobody thinks they're a freak when they're born but one learns over time when being harassed relentlessly from elementary school into your 40s in the office. Yes, that is a thing. The people I thought were my friends along the way turned out to hate my guts, and my own family thinks I'm damn weird so we barely speak. I never fit in anywhere. I'm deliberately disinvited from social events/groups. I understand exactly why and don't even blame them anymore. I read a book on Asperger's a few years ago and it was a lightning bolt that illuminated the previous 25 years. It was me on every page.
Then all at once in one day, when I found out that the one exception in my life who I thought saw me, believed in me, understood me, and who had showed me great kindness turned on me to advance their own career (I mentored them for 5 years until they got promoted to my same title). I couldn't bear it. Was so despondent that I was committed, lost my job and my best friend. This after a successful career trajectory built on decades of working myself to death to compensate for my social issues. Haven't really left the house much for 3+ years since except for food. No idea why I wake up in the morning.