So a regular client came to me with sadness in her eyes as her only 3-years-old new master bath had started to look like a slum. Specifically, the grout had not been done right, and was starting to seriously funkify: 
If you look closer at above pic, you can see that there was no grout placed under the glass shower wall at left, so crud and weirdness had begun to build up in the trench. Looked WAY worse in person, Also at the top of pic, the meeting of far wall and floor was crudding up too. A closeup of floor:
Numerous mistakes had been made here, the worst of which being they had used unsanded grout, and so it had shrunk and had let mold grow and it was no longer flush with tile surface etc. etc.!!
So I ground all the old grout out with a dremel tool and replaced it with matching sanded grout:
Note I also grouted under the glass wall, and sealed it up with clear silicone. I also caulked at top where floor met far wall, with matching color caulk. Now it looks nice. (Pardon the splashed water) Closeup:
