To me, intensity tells me that i'm rising above status quo by going to failure or beyond. If i'm going to failure, meaning i'm fighting like hell to eke out that last rep and am uncertain to achieve it, or if i then cross over into forced reps, negatives, cheats, etc., THAT'S intensity, that's what's going to make the difference and shock the body into growth vs. same ol same ol. Intensity and going through the motions should be at opposite ends of the spectrum.