Also, each sailing on each ship on each line is somewhat different. I've noticed it and had ship's employees say the same. Every cruise has a different mix of people and a different "personality". You can increase your odds of finding the mix that you want by choosing cruise line and itinerary, but it is still partly just random luck. So, you might as well go with the attitude that you will appreciate whomever you meet and have a good time whatever happens..
Marty