Loners live among the mob, so the mob mistakes us for its own, presuming and assuming. When the mob gets too close, the truth is revealed. Running or walking away, chased or free, any which way, we tell the mob in effect I don't need you.
We believe that whatever feels at first like joy is not. Or is, but will not last. Or should not last. We feel so sure of this that we will undermine our own inklings of joy, blunting the pain we think awaits.
And as experienced as I am, it still summons an act of bravery from me, and I like that. I like the idea of setting an example - proving that it is acceptable to be alone in a public place where everyone else is in groups, and to just be sitting there eating, not having to be engrossed in anything else.