Hammer the little critters with the sword in Moonstone *splatt* - nothing left but a puddle of blood and fur. They're so CUTE.
Driving under a trailer in Lotus II - hearing the guy screaming "Yeeeehaaaaw".
Hitting a perfect ball in Nick Faldo's Golf (which is so hard, because you have to click twice with the mouse inside that small indicator).
Shooting ships in Pirates! Winning a swordfight in Pirates! I love how you can keep stabbing at him after he's surrendered. I always hit him one more time before the game continued. Finding the Silver Train or Treasure Fleet in Pirates! was also very satisfying.