wrong plumbing

I see lot's of interesting things on my jobs. I was fixing the alignment of the lav faucet here and when I went inside the cabinet, I saw what I saw on the left. My mind was going wonky looking at it so I pulled a new p-trap from the van and cleaned it up a bit. The fix is on the right.

Hi all, We recently had our house remodeled and built 2 new bathrooms. There is a really bad smell coming from one of the bathrooms, apparently from the tub. The more we use the bathroom, the worse it smells. We tried vinegar, etc., but it appears to be an incorrect plumbing. The contractor...