No one expects kids to be perfect. They do get tired, out of sorts or just plain bored.
They do from time to time play up.
But running, shouting, screaming, kicking, biting and swearing in a public place is unacceptable, unless that child has special needs.
Half the time the parents look the other way, or shout back at the kids. Then wonder where the kids pick up their behaviour from.
The amount of times I've heard a parent threat what they are going to do, then they don't do it!
So the child learns to ignore any threats.
What's wrong with teaching kids to behave BEFORE they go out?
Everyone has off days, but some teachers are now complaining that they are getting 4/5 year olds in school, who are not even potty trained.
And have never heard the word no.
It's a sad state of affairs.