When we "think of" something/someone it is a passing thought, not a deep and/or analytical thought. When we think about something it is a sustained period of reflection on that thing. So, basically, it's the time it takes. "Think of.." will be just a few seconds, "Think about..." will be longer. I would also say "Think of.." is an opinion. "Think about.." is a process or detailed and more considered opinion. Hope that makes sense to you! Phil

"Thinking of you." (more intimate) "Thinking about you." (less intimate)

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