I haven’t heard of most of these that have been mentioned

I do rub the ends of my cucumbers (DH’s Nonny taught me that) and I do think sometimes it draws some liquid out… sometimes cucumbers can have a more bitter taste!
ETA: you don’t rub the 2 ends together, you cut off one end and rub it around in circles on the edge of cucumber to draw a bit of juice out, sometimes it’s clear, sometimes it’s white and pasty. Then you cut off the other end and rub on that side. She called it milking the cucumber.
I don’t throw salt, I will step on cracks, I won’t pick up a penny (even if it’s heads up, lol)