Only when ordering or eating ice cream, LOL. Otherwise they seem to always have a sourpuss expression. Either they absolutely hate the cameras (which could be attributed to comments their parents have made to them and influenced their attitude)...or they have grown up with the same chip on their shoulders as their parents...or they are just miserable. Probably all of the above.
They surely do not seem like happy, giggling, carefree children who enjoy life...or who are especially glad to have all the advantages they have, even with SS around, etc. Never noticed continual sourness with any previous kids in the WH, of any president.
I bet the WH staff could tell us some stories about unpleasant behavior also. And probably about a lot of unpeasant arguing and behavior of the parents, too. Kids are a reflection of how they are raised and what is going on at home. No matter how Barack and Michelle claim to have a happy marriage, and how they put on a front of a happy famiy...the looks on their daughters' faces (most of the time) do not validate those claims.