many guys in the gym doing exercises with weights tat are too heavy for them to managed. therefore, other musccle groups and momentem is being played. HENCE, LESSER STIMULATION TO THE PART! LESSER GROWTH, SLOWER RESULTS!!

Here's another few reasons for such behavior. They are too inexperienced to know what's heavy enough or too heavy. Heck, they might even have less experience lifting weights in proper form. Another is that they get intimidated/ashamed with those who are able to lift really heavy weights in the gym. For short, they need to learn IGNORE all that. Progress on own terms FTW.

enuff said