Here's an embarassing moment, when I first started playing a few years ago, I started as a CNJ. On my hotbar I had stone 1, with a little 50 in the corner of the skill icon. Unbeknownst to me, I thought it was saying that was how many stones I had left to throw, rather than how much MP it cost to cast stone 1. So when I went out to fight my first marmite, I almost died because I only used auto attack. I ran away just in time before dying and then actually read the tool tips.