I haven’t coached little league eight years but I still remember.
One year at practice I brought the parents out to home plate and had them, one-by-one, simulate a hit, having them run to either first or second base, depending on instructions I would give them as a first base coach. I had the kids stand behind the home plate fence and yell out conflicting advice to them as they ran the bases.
After the exercise was over, the parents confessed that they couldn’t understand all the kids’ shouting and it made the base-running more confusing.
I thought I was brilliant and had taught parents a valuable lesson. When the first game came around, the parents didn’t change their behavior a bit. They continued to yell out (conflicting) advice from the stands so I never tried the exercise again.