I'd agree with the comments that say that Five Guys has one of the best fast food burgers in existence ... except for the fact that one of the burgers I bought recently had an actual piece of bone in it. I bit down on this, badly cracking a tooth in the process. Two months and multiple dental procedures later, I'm feeling much better, but this wasn't the way I wanted to spend my Christmas season.
Maybe this was a fluke -- I've never experienced this at any of the other Five Guys I've been to -- but it was certainly enough to make sure that I will never come back to this place again.