Hey Steerpike, great thread! I could not agree with you more...
Many magicians/illusionists are so obsessed with demanding that every effect they perform must impromptu without a gimmick, for the simple fact they can end clean, that they actually avoid performing great effects, and miss out on so many magical moments they could have had, only if they had the courage to work on their presentation, instead of letting the effects speak for themselves. If they only would work on their presentation a bit more, they wouldn't have to worry about ending clean because people would be in such awe about the magic they performed. True magic comes from great showmanship, it shouldn't matter whether or you end clean.
Now I'm not saying that ending clean isn't nice, because it's awesome when you have an effect where you end clean. But ending clean shouldn't deter you from performing a multitude of great effects. Work on your showmanship, then you won't need to worry about ending clean. When you have the confidence, people will believe your lies.
A note on THREAD:
This is not a magic trick. It might be an illusion, but people will take it for a sideshow act. This was my biggest complaint about this effect. It's funny, when Wayne brought up the guy from Guiness World Records who can shoot milk from his nose, that's who I thought about the first time I saw the effect.