If kamma is not everything, then what is that?

Kamma is one of the thing that is not ponderable. We experience many things in life, if a fatal accident is often understood as a result of kamma then what about other relatively small things such as forget to turn off the stove, not preparing oneself well enough before attending a job interview, etc.. Is everything not kamma until it becomes a big event? What are they if they are not kamma?