Assertiveness has never been my strong point. Maybe that's why I watch people who are really good at it, read books and take courses on it, and practice whenever I can.
The impetus for my current life's work teaching conflict and communication skills actually grew out of my inability to express myself.
I was a successful real estate agent and company owner back in 80's, and I often found myself in the middle of a heated contest between buyer and seller or with a banker, building inspector, or concerned family member. My default conflict style is to accommodate other people’s wishes, and that isn’t always useful in negotiated transactions.