> one instance of a person who is smart and not happy
This premise does not lead to this conclusion:
> Stupid people are happier then smart people.
Which is your first sentence and seemingly the thesis of the first comment.
> Kids are generally stupider than adults.
Yes, granted this may be true but my point is there are also a lot of differences between kids and adults independent of intelligence. Ones that can quite obviously affect happiness. Such as, say, social pressure or other obligations.
I can rewrite your first comment as:
"Loners are happier than social people. Look at kids. Kids have less social obligations than adults. They're also happier. So if anything that proves that social obligations don't make you happy and it hints at the possibility that not having social obligations actually makes you happy."
and this is an equally valid conclusion as the one you came up with (thus both are kind of meaningless).