Probably when I found out I have Alexithymia (tldr; it's a 'personality 'trait/disorder that prevents me from experiencing emotions, reading emotions, empathising, appreciating others emotions (it annoys me when someone is emotional around me), limits my imagination, etc; basically, in a world of colour, I can only see in black and white).

I told someone I considered a close friend about it, because she'd always been so supportive of pretty much anything and everything. Needless to say, I guess she got offended and took it to mean that I had been faking our friendship the entire time; I was just a "manipulative bitch who isn't capable of love" and the usual stuff. She then went off and told everyone I was a sociopath and some other things that I can't remember. I lost a lot of people who I considered close friends, because they were scared of me or thought i'd been lying to them this whole time.

It made me realise how fragile relationships could be, and I think at some point I just made the decision that the burden of having people around me wasn't worth the temporary high. Now I'm fake as fuck, because that's how I need to be just to survive in a world full of emotional people.