Realisation
From Experiments in modern living:

People used to think that the world was flat. Pretend that you believe that the world is flat, after all, everywhere you look you can see that the land and sea are basically flat. Now a friend tells you that the Earth is round and you argue with them - look at how flat it is - and you think your friend is an idiot.

For a while I've agreed with the sentiment, "don't believe, just know," but this article opened my eyes. I didn't truly understand until I read this. I now look back at even recent things I've said to people and I regret saying them. I feel like a fool.

But I look at the alternative. If I make sure never to accept anything blindly, how will I ever have conversations with people? Opinions invariably leak into things and that's really what gives the relationship spice. I guess I have to learn to actually think things through, to have patience and humility. To accept that even things that seem so obvious and real could easily turn out to be illusions or lies. Indeed, many things I take for granted I already agree are illusions, but intellectual knowledge is not the same as intuitive knowledge. I know this now from experience (also: here, and here, and here, and here, and here, just to cite a few.)

Edit: Oh, and here's a bit more of the drama.