What I've noticed is one of the main reasons for lack of progress in the gym is that most people are not performing their reps and sets to challenge their body enough. (stomachfatisugly.net)
As a result, my adviser was growing irritated with my perceived lack of progress on his projects. (sciencemag.org)
So, if you are discouraged by lack of progress, keep it up, you will eventually see results. (catchingseeds.com)