The Way We Say the Things We Say..."SHIT" - the Ultimate Basis for Comparison

So I was out and about one evening, and I overheard a guy saying, "man, it's cold as shit out here!"

My first thought was If your shit's coming out cold, brother, you've got some serious problems...
My second thought was to think about how much people use "shit" as a basis for comparison:

• In the winter time, it's "cold as shit"; it the summer, it's "hot as shit"
• You ate a really nice meal: "wooo, that was good as shit!"
• You had a little too much to drink: "I was drunk as shit!"
• You watched a comedian you like: "Man, he was funny as shit!"
• Talking about someone who's not too bright: "He dumb as shit!"
• You just got finished taking a test: "Whew, that was hard as shit!"
• Describing someone that's not so attractive: "Dag, she ugly as shit!"
• Talking about an eccentric associate: "He crazy as shit"

Anyway, you get the idea. No matter how many times I hear something compared to shit, it amuses me. How did this happen? How did we get to comparing stuff to shit? I have no idea, but it fascinates me for some reason...

Well, enough of  this, I'm about to go to bed. It's getting late, and I'm tired as shit...