It's what you are accustomed to. I grew up in a 100 year old home with no AC in downstate IL. We had many summer days where the temp and the humidity were racing to see which would reach 100 first.
I don't recall too many miserable days. We played outside, rode our bikes, went swimming, etc.
Now, in my 6th decade of life, I can't imagine a car without A/C or living in a home without it.
Didn't need it growing up, but someone can't imagine life without it today.
If I had to, I'm sure I could get accustomed again....