i distinctly recall the first time i encountered one of the Lake guardians (or was it giratina?) in Diamond, had it low enough on health, and was spamming ultras, slp/paralysis etc to no avail, a couple soft resets too.. after a while i just lost my patience and went for the master ball (i figured, if not now, it's just gonna stay there unused) i was sure it's gonna catch it, i threw it and it shook 2 times and held my breath for the last one and it broke free! i was in awe for a while, and for the first time i learned that not even a 100% catch rate is truly certain. a lesson for life!