Why are men intimidated by strong women?

I'm a strong take it or leave it kind of gal. I'm outgoing, honest, positive and maybe a little bit of a ball Buster. We have to stand up for ourselves. My male bestie thinks I am. Thinks I put pressure on him. I run part of his business. I have to keep things going. So sometimes I have to keep him on the straight and narrow. I'm just straight forward without being bitchy. His new lady friend is opposite. She's quiet, kind of shy, and kind. I'm kind too. I'm just set in my ways. So are they intimidated by a strong woman or find it annoying? I've always been a guys girl. I get along better with guys.