After the incident he dwelled on the issues surrounding the incident.
What would be other substitutes to express the idea conveyed by "dwell on?"
I considered "mull over", "ruminate", "moped about", etc., but these terms don't communicate the thinkthinking at length about something negative, a frustrating aspect of the term "dwell on." Some of these are too formal or don't have association with the negative frustrating nature of the event.