OK! It was my Radar Hud. I used the developer menu and turned on Animation Info. I still wasn't getting anything in the Animation Explorer, but after typing in every word located specifically in Second Life's Internal Animation page, it finally popped up that avatar_no_head.bvh was playing in the SD Avatar Radar Hud 2.1. There is an Etc. button, which brought me to the menu for Body Exp, or Auto Body Expressions. This was on, causing it to play the Yes and No animations built into Second Life whenever I used it.
Thanks for the replies, all of you, I'm glad it was solved!
Edit - It was still weird that it was playing when I used the default bodies, but who cares, it's fixed!