I guess one of the coolest things I ever saw in game happened in Aby Grauberg.
Three friends and myself wanted to go kill Raja for his pants, for some reason. We had myself on RDM, a NIN, a something else that I don't recall, and a Rune Fencer, which was still a relatively new job that I knew almost nothing about. It was soon after its release, and said RUN had his AF set and a Bereaver.
We pop Raja and the NIN tells us all to stay off it for now, which wasn't hard for me as a RDM in empy +2. NIN gets Imperial Decree'd and dead very fast, so the RUN dashes in, saying "Let me try!"
Other party member was hauling *** back to get a brew, while I raise the NIN and tell the RUN "Don't, you'll die trying."
My jaw proceeded to drop as I watched him quite easily solo Raja.
That is what made me want to play Rune Fencer. :D
Yeah, it's not much, but it was cool to me.