My DH loves the shampoo that they provide in the staterooms. As we were doing 2 B2Bs on the Dream this past summer he tipped the guy $20 in the beginning and told him he really liked the shampoo. My DH got 4 tubes a day and wouldn't let me using any of it!
Made me use the Suave we brought from home.
He would squeeze all 4 bottles into a water bottle. He filled up over 4 bottles and duct taped the lids on. As it's about $20 for a bottle from the store, he figures he made out fairly well.
We requested the same serving team for the second leg of our B2B as they were wonderful and already knew what we liked. The first night back our head server asked if we all liked shrimp. We said yes and didn't think anything about it. The next night, they brought us 2 FULL plates of coconut shrimp. We could only eat 1 so they gave me a cover for the plate and a cup of the sauce. There was no way we were eating it before bed as we had late seating dinner. When I first tried to give it to our stateroom host, he tried to turn it down. I told him then he could remove the cold ruined shrimp tomorrow morning from our stateroom because it would go to waste. I got an "Well, okay, I will get rid of it for you!"
He thanked me for it the next morning. 2 nights later (5 night cruise), the head waiter gave us another 2 plates of it. We again took one back to him (it was the last night of the cruise). All I did was lift the lid a little and he readily took it out of my hands. He said that he and his friends would enjoy it when they got off that night! Made me feel good that someone was enjoying all that food and it wasn't going to waste.
And the serving team all thanked us profusely for requesting them for the B2B. They told us that we had no idea what that meant for them. So yes, fill out that questionnaire at the end and mention the excellent service you receive and mention their names!! It is a big deal.
Oh yeah, and we always pre-pay the tips and then stick extra cash in the envelope if they were great (which they usually are).