How would you define a successful life? Certainly mere existence is not living fully. This is what we have (an unsuccessful life) when we don’t think enough.
Dull, dreary, drab, and despairing is no way to live either. That is what can happen when we don’t care about enough things (or care too much about too few things).
There must be a happy medium. How do we give care to only the ones we love without becoming overly attached?
Have you ever heard someone mumble “selfish bastard” while you walked away? If so you have a fairly good indication that you may not care enough.
Try to think like a caregiver.