And last, look at this example: you have 1000 doors, the prize is on door #1000 ok ?
Now imagine that you are given 1000 chances:
first time, you choose door 1, and after the master opens all except number 1000, you switch your choice, and you WIN.
same for number 2, number 3.... till number 999.
last time, you choose number 1000. after the master opening all of the rest except a random one, you switch your choice and you LOSE.
You would have won 999 times out of 1000. I think its transparent as water now