The red line is when you directly affect personal relationships in your life - either emotionally or financially I guess. The red line only happens when someone finds out like your spouse/partner. Up until that point you are satisfying your human emotions - “I won’t go to my grave not knowing or having those regrets like wishing I had done this or that eg like punting”. If your red line is going to be regret or self vilification etc stop now and give yourself a kick up the arse.