People in my generation have not been known as the world's strictest parents. That being said, my ex-wife and I are not the most patient folks on the planet. We went through more than one public tantrum with our two kids. Their mom's response was to calmly say, "We're leaving" and then drag the kid to the car screaming and crying. My response was to - less calmly say, "We're outta here" and drag the kid to the car screaming and crying.
Sometimes, when you say "no" or enforce rules it can hurt in the pit of your stomach, but you know you are doing the right thing. I think, perhaps, that is when you know you are parenting. It's HARD.
Maybe putting up with the behavior too long is what leads to some of the violence perpetrated upon children by their own parents. Since it isn't "acceptable" to spank in public anymore you actually have to be careful about how physical you get with the kids in the outside world. My ex actually had someone yell at her about dragging my daughter out to the car. There was no violence involved, but my daughter was incredibly defiant at one point in her early childhood.