Maybe this has been asked before, but I'm not about to read 340 pages of posts to find out.

What happens when our difficulty is at 1024 but the network difficulty is at say, 300?  Does that mean that we're missing out on valid shares (and potentially blocks) that meet a difficulty of 300 to 1023?

I just don't get how we can only accept shares that are (significantly) higher in difficulty than the difficulty of the coin we're mining.