There are many firearms safety rules as taught by the NRA, hunter safety, individual range rules, etc. But I have always considered these to be the 4 Cardinal Rules!
Other rules may be situational dependent, but these Cardinal Rules work all the time for all situations. Great video!
The story of the guy who was using a gun to drill a hole in his house to run his cable and ended up shooting his wife happened a couple years ago in my county about 20 miles away from me. What a brain trust. Shot his wife in the chest with a .45 ACP.