If you don't develop a mind-muscle connection and feel the target muscle in a peak contracted state, then that muscle's probably not working very hard.
I learned this lesson when trying to build my traps. Despite having done shrugs with over 700 pounds for reps, my traps didn't grow. Once I started using lighter weights, I could actually feel them contract hard, and they grew like crazy. Holding shrugs at the top on every rep for three seconds did the trick.
That said, it wasn't the actual exercise that made my traps grow. It was the manner in which I did them that made the difference. Movement selection is worthless for bringing up a lagging body part if you can't feel that muscle working – getting into a fully lengthened or shortened position – during the movement.
This is why answers like "do deadlifts for a big back" or "do squats for big legs" are inherently wrong. Because it's HOW a movement is performed that matters most, not necessarily which exercises are selected.
Exercise Selection Is Still Important
Granted, movement selection is important, but it's only part of the answer. If someone chooses to squat to grow bigger legs, that's not a bad choice, unless he performs the squat in a manner where the hips are the most loaded and doing the brunt of the work.
Something as simple as barbell curls can be a worthless movement for building bigger biceps if the lifter is swinging the weight up and down, and not loading the biceps by locking down the scapula and reducing the amount of involvement the upper back.
Tension distribution depends on movement execution. So if you want to bring up a lagging body part, then you need to lock down all the joints associated in the execution of the movement so that the tension needed for moving the weight is created by the muscle group you're primarily trying to work.