Add an S to the end of the word and it becomes more then one. Add two S’s and you will end up with one. What is the word?

I carry your junk, and climb with grace, yet you shout in my stubborn face. I’ll give you sass, you’ll call me an A S S, but truth be told, I’ve got more class. I bray, I kick, I take no flack, but I will still haul you back.

Its a crime more serious than a misdemeanor. Its what one knee might call the other.

Nay, nothing is ever perfect, I say. In fact, I prefer this idea, tearing things down is easier than building them up, you see?

I am the pig of the evergreens. I advise against petting me.