When the hubs and I decided to replace the linoleum in our kitchen with tile, every single one of our friends told us to make sure we used a dark grout because the lighter is a bitch to keep clean.
Although that's what we requested, the flooring guy ended up using a really light color grout. We couldn't complain; "the flooring guy" was some dude my best friend was banging at the time and he offered to do it for free to get in good with her peeps.
And anyway, it's like I told everyone who commented on the light grout when they attended a dinner party (read: hot dogs, macaroni and cheese, and beer) that we hosted a couple of weeks later:
"Whatever, drama queens, because I've got a plan. I'm just going to keep swooping a bunch of dirt in there so that it looks dark gray and nobody is the wiser." And look, my plan is already working. Exhibit A: