I'll confess I'm not an expert when it comes to correctly rigging mountain bikes, but I am pretty sure the cables aren't supposed to look like this:
That's the control cable for the front chain ring shifter, and it snapped about halfway through my ride into town on boxing day, far enough from anywhere worthwhile that there was no point doing anything other than pushing on.
Unfortunately (except if you are hill climbing) in failure mode the shifter shifts to the lowest ring, thus limiting me to my lowest 8 (of 24) gears for the next fifteen or so kilometres to my destination.
It took a while. I got passed by a guy on a BMX. Which was kind of appropriate, since I was riding BMX style (pedal pedal pedal coast, pedal pedal pedal coast), although I reasoned it was only fair since the one gear available to him was higher than any of the eight available to me.
I blame the harbour cycleway. I think it hates me, since this is the second techinical fail I have incurred on it is the last half a dozen times or so I have ridden it.