How do you deal with people who one minute are joking around with you and then out of nowhere they are all offended and serious?
Nice to hear from you again. In order to more effectively answer your question I'm going narrow it down by assuming you're having some troubles with an employee displaying some erratic behavior.
As a supervisor, joking around with the little people is great way to satisfy their self-importance needs. The jovial, fun-loving boss tactic can have a positive effect on employee morale, but is not without its limitations. Obviously you'd steer clear of making any jokes about salaries, job performance, race or sexual orientation. Unfortunately though, there are other jokes that employees will get pissy about that you just can't predict.
Many years ago I worked with a dude that I lovingly referred to (behind his back, of course) as The Vampire. You know the guy; pale skin, long black hair, black cargo pants tucked into black combat boots, black metal t-shirts, black trench coat with a Norwegian flag patched on the back and an old military bag (black, of course) stuffed with various vampire reading material for the long bus ride to and from work. Yeah, that guy, The Vampire.
Vamp and the boss had quite the amorous relationship, based almost entirely around their mutual love of professional wrestling. They would have these long, humorous, animated discussions about who got put over, who's a shooter, who never breaks kayfabe, who's the best worker and so on.
One day the boss made a funny about Vamp's favorite wrestler, *Chris Benoit. A serious, disapproving look washed over Vamp's pale face. He immediately walked away, shaking his head as if he was surprised that someone would actually crack a joke about pro wrestling; let alone his favorite wrestler...er, worker. He didn't speak to the boss or anyone else for the rest of the day.
The Vampire was future endeavored at the end of his shift.
That's pro wrestling lingo for "You're FIRED!"
DE, being the boss, you have a unique advantage in this situation. My advice: wish this person well in their future endeavors. Bloodsuckers have no business in the workplace.
*Yes, I recognize the irony, some 10 years later.