Can you post an example?
It is not a puzzle : it is a lottery.
In simple words : Bitcoin mining protocol consist in a hash calculation of a block of transactions, and this hash (a hash of an other hash in act) has to be a number lower than the difficulty.
The difficulty number is very low and there very few chances to find a number lower than low.
This makes zero sense. If your explenation is right, that would mean that an infinite difficulty would lead to instantly block finding, which is the opposite of what is the case.
It would also mean that a difficulty of 2 would mean that it is extremely hard to find a block, which is also not true.
You're wrong, and the users who posted above you already explained it the right way.