I played with the anxiety & depression example, but I didn't get it. Specifically, I don't understand how "doing things" leads to "feeling good" which leads to "depression".
Every minus sign inverts the direction of the change. Every plus sign leaves the direction of the change as it is. More doing things leads (+) to more feeling good, which leads (-) to less depression, which leads (-) to less de-motivation. But more de-motivation leads (+) to more depression, which leads (-) to less feeling good, which leads (-) to more depression.
A fair number of systems created here haven't grokked the behavior of (-), leading to models that don't actually behave as intended. I admit, it took me a few tries to notice, myself. The description given for relationships doesn't help, suggesting that (-) does nothing more than changing ๐กฉ to ๐กซ. Having three options, more (๐กฉ), less (๐กซ), and flip (โ) would have been clearer and more versatile.
