An amateur sociologist's theory...
Strykervet:
Sounds like the guy in the restaurant is just OCD. Maybe something else too, I'm not a doctor. I've seen a guy walking down the street in Capitol Hill Seattle that was carrying his grocery bags, looked normal, he was at least 6'4" and built, and he looked EXTREMELY ANGRY! He kept yelling about FBI and CIA trailing him, every other word would offend adults with baby ears, and all in all, he looked VERY dangerous. But he wasn't. He was just a guy with a mental illness dealing with it and living his life.
The behavior you describe sounds like
Tourette's Syndrome. 'Interesting that you mention Seattle, because I've encountered more Tourette's sufferers (and assorted other crazies) in Seattle (particularly in Capitol Hill and the U District) than anywhere else, even California.
While California is known as "the fruit and nut state", I'd bet that the NW has more crazies
per capita. I think a case can be made that they actually gravitate there. In fact, I believe the reason there are statistically more suicides in the NW is not that the rainy, dreary weather is depressing; rather it's that depressed people tend to migrate there.
Face it, there are countless Americans whose lives stink and who think, "If I can just get to sunny California, I'll be driving a convertible, surfing every day, dating movie stars and picking oranges off the trees".
Then, when they get out there and their life still stinks, there's nowhere to go but north, so Portland and Seattle serve as the terminus point for all the misfits, maladjusted types and outright loonies.
And many of them, unlike the Tourette's sufferers (who seem to project great hostility but tend to be quite non-threatening), actually are fueled by hostility and resentment and can be a threat. Why do you suppose Seattle and Portland are such meccas for the radical anarchist-types currently throwing group tantrums?