Yeah, I forgot the goat puzzle.
And edlglide, that's exactly what happened to me. I had the cocktail receipe written on a paper, then re-written, then throw the papers, write the walkthrough sollution on a paper, realise it's exactly the same as I figured it, retried it with little hope, and finally yelling "Victory!" after getting the old hag to break the glass.

Most of Le Serpent Rouge from GK3 was really frustrating. It was such a big portion of the game and I hated to use a walkthrough on it, but I did. Of course, if I went back and played the game again I wouldn't remember the solutions anyway.

Also, this wasn't really a puzzle, but there was one thing to do in Grim Fandango that got me stuck in Rubacava for many hours. I had no idea what I was missing so I spent a lot of time having Manny talk at the mic in the Blue Casket. Eventually, and I think I used a walkthrough (only time I needed it for this game), I showed the message from Sal to the guy at the table in the Blue Casket and that was it. I just never thought to do it because if I used that inventory item on anyone or anything else, Manny would just read it. For that reason, I figured it wasn't really a usable inventory item so I stopped trying to use it.

The only time I've had to use a walkthrough in Day of the Tentacle was

Spoiler:

when you had to use one matress with the other.

I knew I had to do something like this, but I just couldn't find exactly how to do it. This puzzle got me stuck for ages, so I guess it ranks high in my frustrating puzzles chart.

Mmmm...escaping the skating rink in SQ4. (Zap, zap! You're dead!) :(

Yea, I hated the microscope puzzle too. Took me a LONG, LONG time to get that one.

--BPF

freaking monkey kombat in MI4. :(
i know it's not much of a puzzle...but it still pisses me off.

But that one actually wasn't so bad after you charted out all the options and choices. Probably the nerdy, over-achiever way to do it, but it works...

Oh, and for Runaway, when he refused to pick up that wrench (was it a wrench? I can't remember) from the trough cause it would be dirty...I wanted to hit him. Seriously. I wanted to physically injure him in some way.

Yeah, I hated that part of the game as well. They should have just stuck with the insult theme since I found the sword fighting in The Cure of Monkey Island to actually be pretty fun.

The problem Monkey Combat was that the insults changed if you left the playing area. If you didn't realise that, it was impossible. I mean, there is no reason a bunch of monkeys should change their mind in a few seconds when you are away!

That's why I play the PS2 version now. They already have a chart of moves for you.

I wasn't even aware they changed at all.

Maniac Mansion.

Dealing with that paint blotch on the wall of the room with the bitey plant.

There was one step in the procedure that I didn't consider, yet was so stupidly obvious after I consulted a walkthrough. I almost felt insulted that it was a required step in the puzzle.

puzzles that i had stuck
 

the monkey kombat in Monkey island 4,
the point where we had to awake the giant at the longest journey,
the final puzzle at riven but thus was very clever,

One puzzle in the dig was impossible I think... If I remember correctly it was about operating an alien machine to pick up something but you had to input some data in it which wasnt mentioned anywhere in the game so you had to guess the combination... other than that it was a great game

With the 7th Guest microscope puzzle, the problem is it's really a game, not a puzzle. They did the same thing with a honeycomb "puzzle" in 11th Hour. I liked it (my sort of logical game) but it didn't really belong with the other challenges of the house. So THAT'S why my chart of Monkey Kombat moves seemed to be wrong.when I wandered off for a walk around and came back to fight. Cheers for that deadworm. :)

My nominee is a puzzle in Innocent Until Caught. You had to catch a wasp.and you did that by waving a jar of mayonnaise at it (are wasps really attracted to mayonaisse?) What did you need the wasp for? To explode the mushroom in the sewers which would open a hole into the bank vault of course! Isn't that just SO intuitive an answer? :frusty:

I hear you... was about to post exactly the same thing. There was just nothing to tell you what those coloured buttons did!

I was stuck on that damn thing for months...

They needed a diagram on the wall that kind of explained it or something along those lines.

The Dig was a good game though

monkey wrench in MI2

For me, it was probably those puzzles in SQ4 and LSL3 which depended on your computer's processor to solve. SQ4 ended for me with escaping the Sequel Police in the shopping mall. I remember getting to the top of the rink once, but then I would come down and get blown away.

I was stuck on the LSL3 bodybuilding sequence for ages, because it turned out I had to use each machine 471 times, with no indication that I was doing the right thing throughout.

And let's not forget all the puzzles in Discworld. Grar.

Remembered another classic. The machine at the end of Phantasmagoria 2 : A Puzzle of Flesh. It just seemed like a bunch of hotspots you clicked at random in the hope they'd do something. Even when I got a walkthrough to solve this one I couldn't see any logic to the series of actions required.

The real problem with it was that you had to watch the dog-slow animation for every turn. It was a classic example of developer error IMO. Never bore the player with lengthy repetitive animation. Probably 99% of the game time was spent waiting for your turn.

... which reminds me of the underwater part in Grim Fandango. It took forever for that singing guy to walk by you. And if your idea doesn't work, you gotta wait another few minutes for him to come back. And that song! Of course, I could do a quicksave/reload, but it was annoying enough during his first couple of passes.