I was surprised at how few Americans were on our first cruise. This was a New Year's Eve Disney Magic cruise sailing out of Miami, and most of the guests were apparently Latin American nationals (not Hispanic-American, these really seemed to be foreigners). I know it's an international cruise with an international staff & clientele, but I was surprised, sailing out of an American city, that Americans only seemed to be about 15 - 25% of the guests. I heard another American guest comment her surprise about that to a CM, as well. Spanish & Portugese were the dominant languages being spoken around the ship.
Sailed on the Fantasy out of Port Canaveral on our second cruise, and most guests were Americans & spoke English. That felt a bit more homey to us. What I learned on our second cruise is that I prefer sea days to port days. After two days of sleeping in and having fun/relaxing on the ship, I was not eager to wake up early on the third morning to go explore an island. We enjoyed our time on the ship more than anything else on that cruise.