>I keep referring to one person.

I know, and it's still wrong. You're admitting it can be done, but then imply it can't be done because people are to different.
>Since when? I've never felt like crying when i've been shy.

It's a matter of degree. And being shy means you are not emotionally strong. Also, don't confuse 'shy' with 'embarrassed'
>And why would you assume this is a universal response?

I wouldn't. I gave three set categories and know to account for the spectrum that comes with them.