For me, it's not something I roll, it's how my opponents roll - namely, that all damage on a 'Mech tends to be concentrated in one leg until it's blow off, with most if not all other hit locations virtually untouched. I've had that happen to me with Stalkers three times in a row. Two got legged with only one single other location ever having received a hit, and one had something like 5 points of damage each on one arm and two torso locations when it was legged. No kicks involved. (I want to like the Stalker, but ever since I irrationally stay clear of the design.)
Beyond that, falling after missing a kick and never getting a DFA to succeed are the two most commonplace fails that spring to mind. Not truly epic, more like making me facepalm and groan.