LUCK
I would have to say that for those who move in retirement there is an element of luck involved. We did our homew*rk before moving (visiting our proposed new state 12 times.) We spent about 6 months total here before committing to the move. I think we spent about 5 weeks in one visit "practicing" what it would be like to live here (where are the best places to shop, where is a good church, what about long-term weather, living on a rock from which the only escape is a 2500 mile flight, etc.).
But with all that preparation and homew*rk there are things you can't know or didn't think too much about or simply got wrong in the knowledge gathering phase.
The things we got wrong (in at least a somewhat negative way) included how to deal with our travels back to the mainland. There are silly things like renewing car tags when you are 5000 miles away. Finding the right person to care for your condo - someone ready to shut it up if a big storm comes along. Dealing with mail. Many financial institutions do not allow forwarding of mail. I could think of more if I put my mind to it. Suffice to say that we have figured ways around most of the idiosyncrasies of keeping one foot on the mainland.
The "good" luck stuff include (what we consider) very good health care. We found good doctors/clinics/hospitals with relatively short wait times with very caring medical professionals and state of the art facilities. Some cancer treatment can require travel to the mainland but usually only for life-extension care.
We thought we had done our due diligence on taxes, but it turns out state taxes are MUCH lower than we had predicted because of our mix of income sources and our status as kupuna (elders.) W*rking in the Islands means high state taxes. Retiring here means much lower taxes. Our overall taxes are significantly lower here than they were on the mainland.
We were concerned about politics. Those who mentioned that they couldn't stand a given state because of conservative politics would love Hawaii. But though we're pretty much "middle of the bird" we find that politics here are more "organic" than say a state like Massachusetts or New York where politics seem a way of life. Here it's just a part of the Aloha spirit and there is very little meanness in disagreement.
Friendships are difficult to develop here because locals have been burned too many times by haole moving in, getting close and then going "back home." We got lucky in finding friends almost right away. That doesn't happen to a lot of haole. For instance, we're often invited to family luaus for holidays.
I think you do make your own luck to a certain extent. We have been willing to adapt to our new homeland and do not insist that people should "do things" like we did them "back home." We embrace being a minority because everyone is a minority. No place is free of prejudice but most people here deal with their prejudices rather than embrace them. We're described as a "melting pot" and within limits, that is very true. A smile goes a very long way here. YMMV