I have noticed something over the years. Pretty much everyone has some kind of tilt bend, shift, and or rotation in their body that makes their movement less free and efficient. Now often these things are born from habits of motion that ask our body to adapt best to what we ask it to do most often. So carrying a heavy bag or child mostly on your left side might bring about a shift of your ribcage and a tilt of your pelvis leaving you more vulnerable to future injuries. (I was going to make a different point in this post, but i will save it and roll with this one). When they warned us not to make funny faces cause they might get stuck that way they were on to something. These things can be helped, but it is easier to minimize them, the whole ounce of prevention and pound of cure thing. I encourage you to challenge your self and your kids to brush your teeth with the other hand. Throw with the other arm. Kick with the other leg. This can be uncomfortable and difficult in the beginning, but if you make a habit of it you will likely be better off than most down the road.