The latter. In 17 years my child has thrown a precisely one fit/trantrum. It was in the middle of Sea World, I sat down on a bench, didn't give her her way, let her scream it out, and when she realized a tantrum didn't work to get her her way, she never threw one again. Beyond having a good kid, and nieces and nephews that know the drill, I'm also good at time management.
I also don't think people are talking about whining kids, it's the full fledge screaming their lungs out can be heard from produce to the garden center on a Saturday in Walmart that I'm talking about.