I am an infj and the Crais motive is stupid. I fully understand the "motive" and it could have worked if the way it was explained and presented didn't suck so badly. Just because we can give Crais an excuse doesn't mean its logical or realistic or that the writers did a good job. It was stupid and 2 dimensional and had faux depth.

Fearless, have you ever taken the Myers-Briggs Personality Test? Your failure to allow for Crais' emotional response is telling. One wonders whether you would tick the box of INTJ/ENTJ in the Myers-Briggs.
Bored now.

It makes perfect sense to me. He needed someone to blame for his brother's death so he blamed John. People do this all the time when they mishandle their grief.

Of course it doesn't. But he just lost his brother and he focus on the cause, Crichton. If John wasn't there, his brother would be alive. Then he tumbled into madness.

i've always considered the story arc of Crais to be one of the most impressive i've seen.
he began as this 'insane military commander' hell bent on revenging the death of his brother, and by the end of his 3 season story he makes the ultimate sacrifice (though not implicitly to save John).
aeryn was forced very quickly to adapt to her new forced life. as you said crais is a man of passion, and it showed in everything he did. his fall from grace didn't have the support system aeryn did. his only personal life he knew, his brother, had just died. that was the one thing that the peacekeepers couldn't take from him, and one day in his eyes john does. i see it as potential expected outcome when you uncork a man who has been bottled up his entire life.
if you've never seen an elephant ski, then you've never been on acid.

Craig is a man of passion. He lives in a society that requires him to repress them. Until his brother's death, Crais was in control of his career and his universe. When his brother was killed, that was the end of sanity for Crais. Irrational was his new baseline. All he could see was revenge. Insane being the operative word from the introduction, it's believable. He IS an alien species, after all.
Great white sharks are attracted to death metal music.

I read about that part. To me, it's a really weak explanation for his behavior regardless of whatever responsibility he felt towards his brother.

No offense, but They explain in my opinion why Crais acts this way pretty well in the show.
Crais father put the burden of taking care of his brother on him at an early age. When He died Crais felt the guilt of not living up to his fathers expectations and decided to manifest that anger and guilt onto the first readily available target he could find, which turned out to be John.
His motivation makes a lot of sense when you look at it in that context.
"What color is the boathouse at Hereford!?"
-Sam

Just watched the episode where he said he was "Shanghaied as a boy". Bad writing.

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