Depends on the audience and the group. If playing with a more juvenile group (could be a bunch of young children, could be just drunk adults) it tends to get goofy.
On the otherhand, most of my groups are pretty serious. They are serious in their gaming and serious at the game table. They may make jokes or joke in a situation, but in general, the campaigns are serious and the game isn't a comedy.
The biggest difficulty comes when I have the two opposites come together at the same table. Then it comes down to melding the playstyles together. At times it seems it makes those who are more in a joking light style turn into the villains of the game and those who take it more seriously are the ones to try to prevent the villain from spreading chaos upon the world (or building...whatever the stakes may be).