One of the first video games I owned was FFXII, gifted to me for Christmas after I had finally saved up and bought my own PS2.

I did not understand how to play the game well. Basically kitted out every character as archers, and if I ever struggled (which was frequently) my go-to was to chain mist attacks and use up all my mana at once. I would often sure a lot of time just waiting for mana to regenerate after any had fight. It was slow but worked, until the bomb king boss in the forest. I would finally kill it, and then the thing would revive, and I would have nothing left. Tried and tried until I managed to kill it a second time and it revived again.

I gave up out of frustration. Came back to it a couple years later, a little bit wiser, and found the game much easier when the different characters had different roles and I didn't blow all my mana at the first sign of trouble. The bomb boss was actually a breeze, and I noticed this time that each revival was with fewer hp than before, so it only revived 3 times before it was done for good.