Please provide a reason for such a trap being better than the absence of the trap, rather than the trap being better than an even more unfair trap.
What? I never made such ridiculous statements, why should I provide reasons for something I never said? Whether something is better than something else in a level depends entirely on the level in question and the particular screens.
Okay, provide a reason for such a trap being no worse than the absence of the trap (which you definitely implied VERY heavily - "I really don't understand what's so bad about surprise traps," "I think it's safe to assume most players have no problem with surprise traps in general." But you already did and I responded, probably not to your satisfaction, so yeah.
games that aren't Knytt Stories
I guess I wasn't specific enough. I was talking about surprise traps in Knytt Stories. See my explanation of why they work in Spelunky, and why they don't in KS. Also keep in mind that "this game has a flaw" doesn't mean "this game is a bad game." I agree that many of the traps and some of the puzzles in La Mulana were stupid, but those are far outnumbered by the puzzles that are fair and fun to figure out, not to mention all the other, more tangentially related things that make the game fun.
The "in Knytt Stories" bit clarified a lot, thanks. Thing is, I don't see KS as a game with a fixed gameplay pattern, whereas you apparently do. One custom level may feel genuinely dangerous, other may be a completely safe, pleasant walk. Others may be little more than living paintings, with the player doing nothing but staring at the environment, and still others may be experiments pushing the boundaries of KS level design logic (e.g. Lingon's "Find the Bug"). This is why I can't reply to "how a surprise trap is no worse than the absense of a trap" - it depends wholly on the level. In a very hard challenge level, for example, both situations are possible; a surprise trap may be perfectly in tune with various challenges (like I described before, making the level
feel dangerous), but it also may be completely out of place if it follows a series of particularly hard screens.
In La Mulana, I would consider
nothing to be stupid. I think that game is as perfect as games get. It was meant to provide the player with a difficult, unforgiving environment; hence the surprise traps and things that can break the game. Sure, I agree some may be irritating, and breaking the game is never fun, but if the environment is right, if the traps are in tune with it and the gameplay, then they're OK. Gameplay logic should coexist with environment logic, I think.
Anyway, given some other statements you and I made earlier, I guess much of this is personal experience; you get stuck in an unfair trap in La Mulana and consider it stupid; I get stuck in the same trap, I use a few swearwords, then continue from the last appropriate save and never for a moment think that the trap was stupid. Maybe we should leave it at that.