I've mostly ran into issues where the host is not able to work out a significant issue (unresponsive for days, does not provide access to property, property smells so badly of smoke you cannot breathe adequately - as a former smoker this is a high threshold). This is not technically a cancellation but an "ended stay" and you are not able to leave a review once you have entered the property in my experience. That said, I'm sure it's improved (hopefully in the year+ I haven't touched it)

In general, it's been extremely difficult to read between the lines on reviews since they're all five stars, and sometimes you end up reading things unintentionally.