Yeah, the original episodes always had those great twists. The later series just relied on SFX. Serling had a way of tapping into the nightmarish recesses of our minds and putting it on the screen. I still remember as a kid fearfully looking for the boogyman on the airplane's wings whenever I was on a flight just like the William Shatner character did in one of the episodes.
Shatner was in another good TZ episode where he becomes obsessed with the fortunes spewed out by a fortune telling machine.