Two years ago me and my friend went on our first cruise on the Galaxy (Celebrity), we are both in our twenties. We knew that we had to tip but we really didn't know how much. Anyway to make a long story short on the last day (in Puerto RIco) we put a total of 40 dollars in an envelope and gave it to the girl who was tendering our room. I believe we checked off two people on the envelope, I can't remember. Now mind you now we only had a couple dollars left so we could catch a cab to the airport. We literally could not afford to give what we did not have. We were travelling on a budget. Anyway I handed her the envelope. About 1 minute or 2 passed and there was a knock on the door and she handed back the envelope with the money inside. I can't remember her exact words but basically she told me that I had to put more in the envelope. I took the envelope back and closed the door. Me and friend bursted out laughing in total shock. I was under the impression that we did not have to tip if we did not want regardless of the service. So we put several more dollars in the envelope and handed it back to her and that was it.
I felt bad because when we got off the ship, we could not even tip the people who helped us with our luggage. They cursed us off in spanish.
What a calamity.