Well, for one, the background is too light. You can see the shadow too clearly. For another, I don't think you conveyed "touch" to the majority of voters. Right or wrong, they probably just didn't see the challenge in your photo.
Also, compositionally, it's rather dull. Not much going on in the photo, no real "wow" factor (and I think we've established that it's sort of required), and the thorns are too concentrated in one area there.
It worked for me. I think compositionally it would have been stronger without the reflection in the background, and maybe rotated 90 degrees so the stem is vertical. Also, watch out for the burned out areas (lower exposure, something to soften/difuse the lighting, etc.).
The background is black tile, and I thought the faint reflection was kind of interesting.
I tried vertical but the thorns didn't look very realistic that way.
The extreme lighting on the thorns was intentional it just seemed sharper (as in pointed) that way to me.
I guessed that some would not like the negative touch approach as apposed to the positive soft and cuddly approach, but I really thought it would do much better than it did.
IMHO, it's the horizontal lines. Your Mirrors entry had the same problem.
Horizontal = Bad ??????
No. It depends on the image. With this one it seems that the image would have more strength vertically (with the thorns pointing upward - rotate 90 degrees CW).
BTW. I like the orientation of your mirrors image, though a slightly larger mirror might have worked better.
I don't agree that horizontal composition is something bad or less interesting. I also don't see why adding somebodys hand (overused in this challenge much toooooo much - I almost couldn't look at the hands anymore)would make it better.
I like the subject, it's easy to "feel it" as it was described in the challenge rules.
I gave it an 8. The background is even too light IMO, not to dark - I thought it would've stand out more if there was more contrast between the background and the thorns.
I think it ended up much too low. I saw other pics of thorns in this challenge - lucky enough not as many as the hands in different configurations - which means it wasn't such obvious idea. Most of them was "touched" by human hand (again) to make it more "explicite" I guess. This one was one of the best.