Wikipedia defines common sense as “knowledge, judgement, and taste which is more or less universal and which is held more or less without reflection or argument”
Try to avoid using this topic to express niche or unpopular opinions (they’re a dime a dozen) but instead consider provable intuitive facts.
My explanation is better:
There’s three doors, of which one is the winner.
First, pick a door to exclude. You have a 66% chance of correctly excluding a non-winning door.
Next, Monty excludes a non- winning door with certainty.
Finally, open the remaining door and take the prize!