I believe the main point was to isolate your emotional state from impacts, and not to "be happy about bad things."
You have to maintain your well-being in the long term by being friend to good people and, well, not being shot, but in the short-term reinforcing positive thinking might just save you from a worse situation.
You have to maintain your well-being in the long term by being friend to good people and, well, not being shot, but in the short-term reinforcing positive thinking might just save you from a worse situation.