To be introspective means to look inward. Introspection is often used as a way to better oneself, to find ways that one could be better. When introspection occurs, one is often examining themselves as a response to some tragic event. It involves not only examining how the event will impact oneself, it involves looking at your mental processes and how you handle emotions.
In the most heart-wrenching introspection, one pretty much tears everything down to the base and starts over. It is often used in psychology to help diagnose issues and help people overcome mental health blocks. No one calls it introspection in the field, but that’s what it is. Interviews, surveys, etc. can all be defined as introspection if done in the right setting.