I've started going to failure (or near failure) on some of my sets like dumbbell curls and lateral raises. Learning to tolerate the discomfort of genuinely hard training is easily one of the most important skills that novice lifters need to cultivate. Learning how to train sufficiently close to failure is the underlying stimulus that triggers the entire muscle building process. For months now I've been mentally limiting myself. In reality, I think I have a lot more to give.
If you're not making the grinch face from time to time, you're probably not going hard enough.
