@petebrown Not only is your hunch correct, they've done research into it like this one from Iowa State University. As they put it:

"People in the rumination group felt angrier than did people in the distraction or control groups. People in the rumination group were also most aggressive, followed respectively by people in the distraction and control groups. Rumination increased rather than decreased anger and aggression. Doing nothing at all was more effective than venting anger."​