They get your jokes. Or, at least pretend to get them.
Your jokes are funny. To you. And even when everyone else turns their head, your "work spouse" will be right there to laugh with you. Or pretend to laugh with you.
McGee certainly knows what it's like to work closely with a joke machine like DiNozzo. And regardless of the situation, or if the jokes aren't funny, McGee will always be there. Because who else is DiNozzo going to crack wise with? Gibbs?
Watch NCIS on CBS.