the Jester
Legend
Never really got that. Any character can be beaten by a challenge with higher numbers on it. And the DM can use any monsters, traps, deities, whatever they want. It's literally just a question of writing down a higher number than the other guy.
Tomb of Horrors is the opposite of "just add higher numbers". It's the most challenging and fairest adventure D&D has ever seen. It is quite possible for a low-level group to work their way through with a cautious and well-thought out approach and suffer no losses.