Just read every post, nodding my head at some, laughing out loud at others.
I raised two sons pretty much by myself after DH left. Made me a pretty tough, self-reliant mom I can tell you. I had some pat answers to their "challenging" behaviors: "ewww, I don't like this (what I had fixed for dinner)" - answer: "this is not a restaurant and I am not a short-order cook, you can fix yourself a bowl of cereal or a sandwich if you don't like what we are having for dinner." Or....."you're the meanest mom in the whole world!" - answer: "No, Mrs. Virginia Jones in Kalamazoo, Michigan (made-up name) won that award, I was only first runner-up."
We often made the hour drive to visit the grandparents; if the boys started whining or fighting with each other I just pulled over to the side of the road, stopped the engine, got out of the car, shut the door and patiently waited where they could see me until they stopped. I only had to do this once as they got the hint that further bad behavior would mean a longer drive to get to the grandparents' house. "Do I have to stop the car?????" I also did this maneuver with my friend's children while we were all driving hours to the coast (with my friend, their mother, in the car!) Cured them of their bad behavior too!
Good advice: choose your battles! Hair, clothes, and clean rooms are insignificant in the larger scheme of things. This especially applies to pre-teens and teens.
When he was a teen, DS#1 got mad at me one day over something I wouldn't let him do and yelled "well....I'll just go live with Dad!" I calmly said "that's fine....let me help you pack!" as I walked toward the stairs to go up to his bedroom. Within a minute he had changed his mind and was apologizing to me for his behavior. He never did that again and never went to live with his dad.
For several months when DS#1 was in high school, a friend of his lived with us due to tension at home between him, his mom and her new husband. I treated him just like one of my sons: fed him, got him to school on time, made sure I knew where he was, made sure he phoned his mom regularly, saw to his homework, worried about him, etc. In all that time, his mother never talked to me, never called to ask how her son was, never thanked me for looking out for him, never offered to help with money for groceries - nothing. I still have trouble understanding her behavior to this day.