The darkest I have encountered, for myself, especially in connection with depression, is OGA—Online Go Anxiety:
I was able to overcome most of it when I discovered the first Go server where I could play correspondence games (Dragon Go Server). That way I could also chat with my opponents and make friends—and I realized that, for me, this OGA doesn’t exist when I play with friends. And usually I treat acquaintances as friends
And then there is this phenomenon of bad conscience when I realize that I am winning a game and could have stopped destroying my poor opponent many moves ago and just go on closing borders and fortifying weak spots.
Some games that I win feel really brutal to me, especially with beginners … however not with all beginners—some clearly say that I should play my hardest, and then I don’t worry about their feelings.
But otherwise it really is a test for my conscience: ideally I’d just be able to do it like strong players: count and make sure I win by ½ point but no more, which fits in with what little I understand of “Eastern philosophy”, Buddhism and Eastern martial arts: use the least force necessary to defend myself, but no more.
Well … I’ve read that in Japan there’s this saying that “Go is a mirror for the mind/soul” … I don’t always like what I see there but to me it seems to be a good exercise to confront myself with who and what I am.
So… not dark in itself, but a rather tool for introspect, for checking what darkness there might be inside