I got to experience this when I visited Punta Cana back in 2012. It was the first time I had ever traveled to another country, besides the USA, and it was also the first time I traveled without my family.
We went to Punta Cana after graduating high school for our grad trip and it was an amazing experience. Spending 10 days with your best friends, free from high school, at an all-inclusive resort where it was all-you-can-eat and all-you-can-drink!
We stayed at the Barcelo Resort in Punta Cana and I personally, as well as my friends, had a great time and experience. It was amazing to not have to worry about paying for anything when you go out to eat and it was definitely amazing to have free unlimited drinks! Each night there was a different theme to have fun with including tight & bright (in a cave!!) and toga night! I did one excursion while I was there which was a jeep ride through one of the towns closest by, but some of my friends also did the Catamaran excursion!