Why aren't I going with them?

I’m also in the, “why am I not” camp. That sounds right to me.

Amn’t all the way. Even had a thread about it a while ago.

Kind of OT. I did some of my own Googling on this subject and ran across a reference to the following, which turned out to be on Google Books. I’m particular about things like this, but this excerpt did get a small smile out of me. (I’ve added "sic"s and extra paragraphing.)

I don’t know if this is the same person: Andrew Preston Peabody - Wikipedia

“How come I’m not going with them?”

Well, that’s what I’d say.