The thing is, the 'line' is in a different place for every NT, as well. Further, even NTs who are blinded by their need for someone sometimes cross the 'line' as well.
I guess what I'm saying is that you have to do two things: (1) find something else to focus on from time to time, so that you can retain perspective, and (2) even though it's ridiculously hard, try, occasionally, to intuit what the other individual's point of view is, AS AN INDIVIDUAL.
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Hmm...