It’s known as the ‘Brazil nut effect’, technically apparently Granular Convection: https://en.m.wikipedia.org/wiki/Granular_convection It’s apparently not fully explained, but theories suggest things like buoyancy, or that larger particles are blocked from sinking by smaller particles, which on the other hand can slip below the larger ones.

I just walk in and say ‘Good Morning’ in passing, no need for an answer or waiting for them to stop talking. Then I go settle in for the work and if they want to chat they will probably talk to you then. If you were there first I guess you can take the initiative.

First time hearing o7 as ‘nazi salute’, I only know it as a ‘military/captain’s salute’ out of Eve Online, Elite and some milsim games

Universal law of tradesmen: They come when you least expect them, and when you expect them they don’t come.