Imagine that two cavemen sit in the grass on a warm summer day. One is a problem-solver, like us. His skin is broken out and he worries and frowns a lot. Hyper alert, he is often agitated and jumpy. He thinks about the noises outside the cave last night andwhat the rumbling in his stomach means. He walks around, looking for fruit and keeps his eye out for tigers. The other guy sits quietly, counting his breath and feeling the breeze on his face. He’s easy-going and popular among other cavemen. He doesn’t react to what others say and is accepting of different ideas and personalities.