Originally Posted by Bagge
There's no use in puzzles being hard if you cannot solve it by logic. The fun of puzzle solving lies in actually solving puzzles yourself, not by desperately clicking and combining everything until you stumble on some illogical solution cooked up by the game designer to artificially increase the length of the game.
Although a lot puzzles have logical solutions, many many more require lateral
thinking. Thats the secret of a good puzzle IMO.
Use key to open door is logical.
Use monkey as wrench to to turn off a waterfall is lateral thinking. (OK, extreme example)