They do and will happen. The mere word suggests unintentional and is mainly associated with unpleasantness. We say I bumped into someone accidentally or had an accident, and it is not of focused intent. It mostly happens when there is a lack of focus or purpose.
When it occurs with material matters or anything other than humans, we are somewhat forgiving, while we are less tolerant of people. So why do we expect the perfection of others and justify our missteps?
They are accidents, and they will happen. And we are still human.