Related Clues:

• Focus intently (on)
• Belabor, with 'on'
• Obsess
• Think anxiously about something
• Become obsessed
• Stay on the same topic too long
• Ruminate
• Focus intently
• Make one's home
• Live (in)
• Harp
• Harp (on)
• Concentrate (on)
• Take up residence
• Inhabit