I’m having trouble getting the achievement “My happy place”
It seems impossible to achieve 100% clothing in normal circumstances because there are always a few infants in the town who do not wear clothes.
And a Family factor which I believe I don’t have any control over.
So the issue is not related to infants? 14 infants in 1000 pop is 1.4% and 100-1.4 = 98.6 which may be rounded to 99% which explains your screenshot… the infants are all unhappy because no clothes.
If not, then I don’t quite understand what’s going on here.
I’m having the same problem where clothes-happiness never goes above 70-80% even though I have a considerable surplus stockpile of hide coats, linen clothes, and shoes.
In my case I’m at 200 population with about 50 infants and 50 children, so I thought that was the issue.
I cannot tell for sure but what I think of is a rounding problem. So if sum of all happiness factors rounded half up gives 100% overall happiness then achievement will be unlocked.
1.4% is only for one of 12 factors. So this 1.4%/12 gives you only ~0,12% of overall happiness. And if avarage happinness is above 99.5% it is counted as achieved. That is my assumption.

