The first three parts of this critique are written based purely on examination of your photo. "Final thoughts" is written after reviewing your score, photographer's comments, and voter comments.
TECHNIQUE Your conversion to BW has left a fairly flat and uninteresting image. Sure, there are white whites (top edge of the seat) and black blacks (shadows between tank and bowl) but the overwhelming feeling of the pic is gray, gray, gray. Focus is good and I think you've made very nice use of a shallow depth of field. I think the lighting is the big downfall here - the image just feels to blah.
COMPOSITION What's the best way to shoot a toilet bowl? You obviously want to stay away from the sterile "catalog" type shots and your unusual crop and perspective work well for you. You've captured the concept behind your shot nicely, with the seat not up but also not down.
EMOTIONAL IMPACT Hmmm. I "get" the idea (I think), but it's not a real eye grabber, is it?
FINAL THOUGHTS It looks like your commenters (and voters) had similar reactions to mine. I didn't vote this challenge and so didn't look at many of the shots (and therefore wasn't distracted by looking at lots of toilet shots), but I agree that this shot needed something to give it some wow (better lighting) and eye appeal (maybe a model lifting the seat, or whatever). As shot, it doesn't hold the attention or inspire questions, humor, or wonder. Doomed to the middle ground of the voting wasteland!
I agree that enhanced contrast could bring higher votes, but I actually like the edit as simple as it is. Best shot of its kind in this challenge, imo.
I love how you took a different perspective of the toilet idea and got right in there - great work. I'd suggest that you brighten it up slightly and possibly increase the contrast though. ;)
A better perspective and crop on the most common of themes. Lighting quality hurts this image, it seems grey, not black/white. Leaving a feeling of flat lighting where it actually appears there may have been better dynamics in color. Nice use of DOF and good execution on the crop/angle/viewpoint.