OK, I have a good one now:

Finally got scholar unlocked, so I decide to go into guildhest roulette for something easy to try it out on .... and get dropped into Briaxio (the one with the sylphs that hand out all the debuffs). I'm suddenly panicking inside because scholars don't get esuna, but it's a good group and we still clear without too much trouble. After leaving, however, I glance at the party list and it hits me that there's one fewer line than it should have.

That's right -- I'd never summoned a pet. I facepalmed so hard, and to make it worse, I *still* got two commendations out of it.