A friend called me in to look at a shower he had professionally done for his parents. The tile guys walked off the job to work in NC, so he was looking for advice on how to best finish this shower. I told him he needed a chipping hammer and a lawyer.
The list is too numerous, I'm sure I skipped a few;
1- 12" travertine tiles on the floor
2- not enough slope
3- butted floor tiles
4- not enough support, floor flexes
5- sanded grout for all tiles, including the subway on the walls
6- butted tiles in the inside and outside corners
7- who needs a level?
8 to 12 - ceiling
13- the pattern was supposed to be a blend of the two colors
14- no bullnose anywhere
15- drain set higher than the floor tiles
16- corner shelves above eye level
17- sharp tile edges exposed inside the shower
18- thinset left to harden on top of the tile
19- grout mixed with too much water the color is gone
20- The bench height is 24 inches, for a short elderly couple to use
21- And yes, its not a photographic illusion, on every wall the tile grout line sags in the center by a good 1/4" or so.