When you go to the gym, you should know why you're there, because your final goal will dictate how you push your body. You'll focus on the amount of weight you can lift in each exercise if you're training for power and strength.
If you're training to be a bodybuilder, your goal will be to pack on as much lean muscle as possible while maintaining a proportionate figure. Before you start flinging weights around, you must first determine what your goal is.
Bodybuilders aim to develop their bodies in such a way that they flow aesthetically, with muscles that "pop" like they would on a cartoon character. This illusion is enhanced by the presence of profound striations and separations. But what if one body part is dominating another?
WHY IS A BODY PART LAGGGING?
To begin, you must comprehend why one area of your body is not developing as quickly as others. Perhaps it's because you're unfamiliar with the exercises that target that muscle.
Because your form is wrong or your body isn't physically capable of engaging that specific muscle, you may not be contracting it through its complete range of motion. Maybe it's just because you don't strengthen those muscles and instead concentrate on your stronger ones.
Once you've figured out why a body part isn't performing as well as it should, you can address the problem directly, whether that means finding the proper motivation or doing the right exercises. Don't worry if you don't know which exercises will target the muscles you need to strengthen; there are a variety of ways to figure out which exercises will target which muscles.
A quick google search might provide insight into what bodybuilders perform in the gym. You can start putting together a program to boost up your lagging body part once you've compiled a list of 4-5 exercises that target it.
THERE IS NO ONE FITS ALL SOLUTION
Not all exercises are suitable for everyone. There is no such thing as a "one-size-fits-all" approach to training. Yes, most lifters should be able to complete the majority of exercises. However, if you experience joint pain while executing a specific activity, it's likely that you're not using good form or that the exercise isn't the ideal fit for you.
Just because an exercise is beneficial to certain people does not mean you should include it in your workout. The purpose is to challenge a muscle or muscles, not to accomplish a set of reps or an activity. The activity is merely a means to an end. Find the 4-5 exercises that are most effective for you and improve them.