I hate puzzles and traps. They get in the way of my hacking and slashing! Traps aren't so bad, really, as they can usually be detected by competent sneaky types or detect magic. Disarming or bypassing them is another story, and not always pretty in the end.
Some memorable traps came from White Plume Mountain and the godfather of killer dungeons, Tomb of Horrors. The sphere of annihilation trap, pit of molten lava, the stone juggernaut, cursed wish gem, and of course the demi-lich Acererak. Even some of the rooms have lethal-sounding names - The Chamber of Hopelessness. Need I say more?
For my adventures, I seem to recall employing traps using monsters. Green slime (a la the moathouse in T1), piercers, trappers, and the ultimate dickhead combo - a couple of rust monsters and a carrion crawler.
Puzzles are another matter. They can add great flavor to just about any adventure, or they can bring the action to a screeching halt. Sometimes it's a matter of timing - a puzzle at 2:48am always seems exponentially more difficult than puzzles presented in the first hour or two of the adventure.
For some reason, I always remember the riddle from White Plume Mountain:
Round she is, yet flat as a board
Altar of the Lupine Lords
Jewel on black velvet, pearl in the sea
Unchanged but e'erchanging, eternally
The answer is "the moon" of course, and if you figured it out, the gynosphinx in the room will lower the wall of force blocking your way. As I was in 6th or 7th grade at the time, I had no idea what "lupine" meant. But you can be damn sure I looked it up in the dictionary when I got home!
Teachers should take note - D&D is a wonderful educational tool! It can boost reading and spelling skills, among others. Use the lupine example above as living proof.