It's not really the 'greatest', I'm just amazed at how dumb the AI was. Today I was playing Leaf Green, and having transferred most of my team to Diamond, I had a 43 Dugtrio, a 44 Raichu, a 23 Pinsir, and a 29 Slowpoke when I was walking around Power Plant. I saw Zapdos and figured it was worth a shot, forgetting to save before I started fighting him. Dugtrio died after reducing Zapdos to half HP, so I sent out Raichu, whose moveset couldn't do much damage against Zapdos, so I resorted to spamming Flash. Two Flashes were pulled off before he died as well, so I sent out Pinsir.
I looked at his moveset and was surprised to see Seismic Toss. Remembering its damage = pokemon's level, I used it, reducing the Zapdos to the red. All the while Zapdos was spamming Agility. I started throwing ultra balls until I ran out, and during that time he used Detect, which failed, several thunder waves that missed, and another few agilities, not once bothering to Drill Peck Pinsir. Moving onto Great Balls, I was down to my last one, with Zapdos still using passive skills before I caught it. That was the best luck I'd ever received in a pokemon game. Really amazes me how stupid the AI can be sometimes.