Cancun is fine depending on your worldliness. Its close to the mainland US so there are a lot of ways to see it (and Xelha, Tulum, and Playa) that will not break a young person's bank. I was there more than thirty years ago as I had not yet married my wife and could not travel anywhere but North America on a buddy pass. The one thing I remember most vividly was taking a tour bus to one the surrounding destinations and the escort scooted a milk crate down the bus aisle handing out beer to passengers. Safety be damned. Still enjoyed since every place was new. I had already been to Miami so I was not at all disappointed by the overpriced and semi-fake paradise tourist traps. Also, in fairness, I had lived in Hawaii for a nearly a dozen years so I knew what to expect/avoid.
On our honeymoon, a year or so later, my wife and I honeymooned in Hong Kong with a side trip to Bali. In Indonesia, we hired a guide for two days to see what the locals considered worthwhile. At the end of the first day, the guide insisted we pay at the end of the second day. We found the vendor on the streets as locals weren't allowed into the gated resorts. So, they had no way to find us if we ditched them. That was probably one of the most unusual things I have ever experienced. I can only attribute this to my wife's (born and raised in Hawaii) local beliefs, habits and personality. And, maybe her naivety as I am not sure if I would do the same thing today.
But here is the deal. Those speaking badly, of these destinations, likely did not see the physical places that make the destination desirable to those who know it well. And, if you didn't enjoy your experience with locals, it is VERY LIKELY that it was because of your obnoxious superiority vibe turned off the number one attraction (the people).
There are at least a hundred worthwhile things to do while visiting Hawaii and only a handful in its most popular destinations (Waikiki and Maui). An erupting volcano and mountains with snow are two things that few people ever see but can be seen today as we speak. And there are great uncrowded sandy beaches within a short drive from these hot/cold spots.
Here is the thing. If you don't want to be there the local people don't want you there. I always looked at Miami as the poor man's Hawaii and rightfully so. But that likely limited my experiences. Despite its obvious physical/geographic limitations locals (including creep) know it better. Just don't tell him I said that.