Cobalt nailed it. Indoor plumbing!
Here is the set up. The explanation, is that bad things happened on those 2 days, and all scripture is inspired etc... This is besides the charge that primitive Christians didn't celebrate their birthdays which I am not even sure is true.
Anyways, there are only two mentions of indoor plumbing in the bible. Eglong (sp?) was a king that was super fat. One of Isreals judges ran his sword into his belly until he couldn't see it when he was on the .....err.....throne.
Moses mocked a false God during the test in the valley, saying he wasn't answering his prophets because he was "in the privy".
Thats it. A false God in the pooper, and a fat bad king that Jehovah killed through a judge BOTH with indoor plumbing.
That is why I dutifully dig a hole in my yard.