Critical Hit!

I was playing my pokemon game the other day and noticed something. Have you ever noticed how the strongest pokemon attacks always miss when you need them most? I was using Hydro Pump (with Blastoise of course) against a level 100 Dragonite and it missed! Then he used slash for a critical hit and I lost! I would have killed him but I missed. Come on! Then, I used Hyper Beam with Snorlax against a Gyarados and missed! WTF happened?! I know Pokemon is a probability-influenced game, but that just sucks. When these attacks miss, rest assured that you will not beat the Elite Four, or any other strong trainer for that matter.