This guy demonstrates a major gun safety fail and is a good example of what NOT to do when handling a firearm.
The Internet is full of people improperly handling and negligently discharging firearms on video. What makes this gun safety fail video unique is the fact that the guy was saying exactly what you shouldn't do when handling a firearm, yet went ahead and did it anyway.
Pay particular attention to what his dog does after the negligent discharge. It looked like the dog was just as surprised as he was.
This guy very clearly violated two of the cardinal rules of gun safety by not treating his shotgun as though it were loaded and by not keeping his finger off the trigger.
Fortunately, nothing was hurt other than this guy's ceiling and his pride. However, this kind of gun safety mishap can very easily end up with someone getting seriously injured or even killed.
Remember: ALWAYS keep your finger off the trigger unless you are actually aiming at a target and are about to fire and ALWAYS treat your firearms as though they are loaded. It's amazing how many firearm safety mishaps involve supposedly "unloaded" guns.