[slowpoke]

I think the important distinction should be between "traits that have nothing to do with the job". and those that do. Race, gender, sexual orientation, spiritual creed etc almost always have nothing to do with your job (examples such as a priest naturally exist).

Shyness or introversion pretty much also fall into this category, though with a bigger grey area. So no, I don't think shyness should be a protected trait by itself, but the category it mostly falls into should be.

[billybob]

It's a huge gray area. To expand on your point, if you're a socialist Buddhist and I'm a libertarian Muslim, there's nothing legitimate about that difference that makes me unable to code alongside you. We might not hang out, but we can debate the merits of application designs and help each other with bugfixes.

But I'd say personality is very different. Personality is basically a summary of what it's like to work with me. If I'm too shy to express ideas or passive aggressive or so extroverted that I won't stop talking and let you work, that's a real, practical problem.

"I can't get along with you" is a perfectly valid reason for me to quit if you're my boss or fire you if you're my employee. Anything restricting that will create dysfunction. How can this be compatible with making personality a protected class?

Heck, personality isn't even clear-cut like gender or disability is; I'm not clear on how you could even write such laws.