You're... Too Monotonous
"If you find yourself doing the same workout routines--with the same weight--and spending hours in the gym with no results, it's time to take it up a notch. For example, instead of doing three sets of 15 squats and three sets of 15 shoulder presses (with rest between each set), try combining the two exercises to make it a compound move (known as a thruster) and do as many reps as possible for time. This is the basis of a HIIT workout; always changing and always challenging! That's why they're so effective!" --Amanda Butler, instructor at The Fhitting Room