Especially if you're in a hot stuffy costume. Also, remember to use the bathroom before getting into costume. There's nothing more disconcerting than being on stage and needing to use the facilities. If you've been shopping or are lugging around several things you don't want lost or damaged, have a friend drop them off in a room for you. The backstage is not a good place to leave items unattended.
Audiences love short skits.
They also love funny skits.