|The, um, frosting on the cake. aka 'Looking Inwardly Serious.'|
"If it is with outer seriousness, it must be with inner humor. If it is with outer humor, it must be with inner seriousness. Neither one alone without the other under it will do."
But then again, either one alone with the other over it will do as well. As will one or both with the other under it, or over it. And neither one not alone without the other under (or over) it. Any of these is fine ... seriously.