Man, don't even worry. Everyone's had those herpaderp moments. Here's a few of mine:

Myself and some friends were having a fun random night - we do random trials on random jobs in the duty finder. We ended up in Ultima HM with 4 dragoons as our DPS. I'd been drinking quite a bit that night and hadn't played dragoon in awhile; since that time, I'd remapped some of my keys including my push to talk for VoIP. After said remapping, my Jump key just happened to be the same as my push to talk key... Dragoon jump facepull.

My first time getting to Heavensfall, we had a more experienced person with us that was helping out since we'd never made it past the golems before. At Heavensfall, he said "everyone stack on A". I had only watched a guide a few times and I was sort of nervous, so I took him literally and stacked on top of the party as main tank. Needless to say, that was a very very short foray into that phase of T9! I think my party was equal parts amused and unhappy.

I've pulled in T5, T9, and T13 without Shield Oath... I've also tried to use Infuriate as a Paladin a few times now.

There's been a few times where I've accidentally selected a mob instead of the tank. Tank gets critically low on HP, I hit the key for Lustrate... and spam Lustrate on myself as the tank dies, followed by the rest of the party. >.<