Sometimes when I have just appeared to a hostile creature, say, if I unstealth next to a rat, it takes a while to notice me. Now, run with me on this: if I try to use animal empathy on that rat, I'll take 20 and get him in my corner. Taking 20 with animal empathy against a hostile creature; am I glitching out here, or is this some sort of mechanical uniquity? Is it an exploit?

You get to take 20 if initiative hasnt been rolled, I think.

It's a skill -- I guess. Where, if you spam AE enough while coming out of stealth you get to take 20, and AE the creature. I'm not really sure if it's a bug, exploit or a feature. Yet, I know I was pretty good at it when I played a druid.

You take 20 on an AE roll if the creature doesn't attack you.

You take 20 on most skill rolls providing that you're not in combat: disable trap, open lock, animal empathy, etc. This is why the skill DCs for NWN are higher than D&D, where you have to actually make rolls much of the time.