Or had a parent/child relationship or owner/owned relationship across every thread, or installed a journal hook, or... Don't get me started on Window's non-nice

Or had a parent/child relationship or owner/owned relationship across every thread, or installed a journal hook, or... Don't get me started on Window's non-nicety if you want cross thread/process window relationships and want to be able to keep your primary UI thread from locking up if the child thread does.