Any commuters out there would know, as a JS after you say hi to the CA, you probably should have some sort of acknowledgment with the FO as well, either a nod or handshake, or "Hey, how you doing?" Also, it is common courtesy to ask for permission with the FA to speak to the CA.
I always try to make my JS comfy in the cramped cockpit, i.e. take the logbook out of the way so he/she can put their feet on the rack, take the trash bag out of the way, offer a drink before the flight, slide my seat a notch forward than normal...
If someone in my JS pretend that i'm invisible, don't expect me to say sorry when i crush your foot when i slide my seat back, or heck, you better find your own O2 mask when there's an emergency
I really think there should be a presentation for newhire these days for regionals on how to JS. It's so important to do it right, and you just don't want to lose this privilege because of one bad seed to ruin it for the rest of us.