What if you took a recipe to make, say... a helmet. And instead of iron, you used leaves. Or perhaps if you made an Axe. Out of Mud. Or maybe you made a flashlight but you did something dumb and replaced the lightbulb with, like... an explosive or something. What I'm saying is it'd be hilarious to see people mess up combinations and actually end up with these useless things that could even destroy them. It'd be hilarious for the rest of us. And we'd thank you for letting us watch. Agreed?
This has potential to be hilarious, problem being that for this to actually work, you would have to have a crafting system different from the one Terraria used, and more like Minecraft's one, since you can't really mess up crafting something in Terraria. And I'm not sure how I would feel about something going towards Minecraft's crafting method, seeing as I'm really, really bad at memorizing things. I'm already quite glad that Minecraft doesn't punish you for failing to craft something, because if it did, I'd end up with a lot of wasted resources. Though of course, I don't represent the entire community, so if I'm the only one who's just really bad at that kind of thing, I wouldn't mind having to stick with it.
It would be more viable to add items to some kind of "active crafting" area, then applying schematics somehow at least to make this idea work