It was the same for me though I'm not retired. At first I didn't understand it, but gradually I also felt that something wasn't quite right about Pattaya.
Pattaya has been a horrible experience but that doesn't mean the country as a whole is the same. Right or wrong, I get the impression most expats living in Pattaya are just waiting to die. As harsh as that sounds, I never felt that way about Chiang Mai...ever!
It's true that the cost of living is slightly higher, but not really by that much, and it's true that the pollution in Chiang Mai is bad during the smoky season, but that last for only a couple of months, and all it takes is a ride up Doi Suthep (the mountain) to escape that, where the air is crystal clear and cool even on the most polluted and hottest days.
We all make mistakes. As soon as my lease ends in September, I will return to Chiang Mai to finish out my last year in the Magic Kingdom.
You should consider the same if you've never lived there before. If you like hiking and mountain biking, it is actually a paradise that people come from all around the world to experience. And that includes people in their retirement years!