I think it's all part of the learning process. I just recently started playing again, so I started off by grinding marmots outside of Ul'dah, then moved a bit later on to right outside of Black Brush. While mindlessly grinding marmots and coblins, I saw an ant critter run by, so I figured I'd attack it, too, since the marmots hadn't respawned yet. You can imagine my surprise when the thing one-shotted me for 1.5k when I only had, like, 450 health. Taught me not to screw around with random critters that I had no knowledge about.