The Secular vs. the Spiritual, 2

On the basis of "The Conventional Morality" (Sept. 19 (https://www.meetup.com/The-San-Diego-Philosophers-Roundtable/events/140076732/)) and with the moral emotions somewhat explored (Sept. 26 (https://www.meetup.com/The-San-Diego-Philosophers-Roundtable/events/141257092/)), let's examine the tension between the secular and the spiritual.

The moral emotions divide human experience seemingly into the secular and the spiritual. Is Sunday a holy day or just another day? Is "Merry Christmas" a greeting reserved only for the faithful? The secular and the spiritual experiences don't mix in the conventional ethos. Why is that the case? Or should they be mixed? And if so, on what basis?