I think that most people, children or adults, have tantrums when the issue is really something else entirely. The person is hungry, thirsty, tired, cold, hot, worried, stressed, unwell...and something (or someone) else sets the person off or just becomes the unlucky recipient of all that pent-up strain. I'm fairly sure that's what just happened to me. I'd love to wish such things would never happen, but we're all human. We all lose it, fairly or unfairly, from time to time. Someone is going to take the brunt, rightly or wrongly, when we do. Is it best then to just accept this human nature and drop it? Does there have to be a discussion of all the ins and outs and whys and whatnots after an apology is offered?
Observing this with children is so easy. They lose it; they move on. They accept that this is normal, not a cause for deep analysis of a relationship. They don't wallow or fester, waiting for it to happen again. The cool-down period and the apology makes the end, and all is new again.
There is much to learn from them.