Yeah, it's because each "world generation" mechanism is (mostly) independent of the others, which means that things in one phase are done without regard for any previous or future phases.
Well, that wouldn't surprise me since there is one every 100 blocks. I hate hearing sounds of spiders when I'm in a cave looking for goods and they are so freaking annoying that i get mad after few minutes and go on a killing spree! So if anyone is mining in a cave without spiders, then I was definetly there!
I get annoyed by spiders too and want to change the annoying noices they make.. It would be funny to make them sound like the kid from the grudge but then that would probably get annoying too..xD
Good idea, I thought about changing their voices too, but like you said, they would be still annoying. Another annoying thing about spiders is when they get stuck in the block or just in the open.. Happens to me a lot that they can't get to me. I'm standing few blocks away and they are just jumping up and down like they can't move ahead, even though there is clear air ahead. So they are stuck, making noise and you gotta search for them. But when you don't want to fight them, THEN they will ninja you from above.
