Before eating, Louisa and I bow--for me, it's an opportunity to notice I'm alive--literally. I was 30 before I noticed that. I guess I was on "automatic" before then.
Before and after our weekly 'business meetings' we bow to remind ourselves that we're a team, especially in case we get into items we disagree upon.
On trails in Nepal, it was namaste to strangers: I don't know you, but my spirit acknowledges yours.
If I'm particularly grateful to someone (who may have no connection to Buddhism), a gassho is a way of expressing my sincerity. Ditto if I need to apologize for something.
Coming into the zendo, it's a 'memo to self' that I'm part of a long lineage of meditators, to whom I give thanks.
Before and after meditation, a gassho says thank you to me (bowing in to my cushion) and to the group (bowing out) for our communal presence.
In formal group discussions, it can take the place of a talking stick, keeping a semblance of formality to what might otherwise be 'just' chatting. At the end of the discussion, it's a way of saying, OK, we can talk 'regularly' now.
When Louisa and I need to connect after some awkwardness or upset, it's a way of cutting through our BS.