PSA: please no one let me go into an upper body session with no plan because 10/10 times, I will resort to my favourite exercises: bench press, and a bodyweight/calisthenics-based back workout. -
However, my back is not the strongest, the leanest or the most muscular back I've ever seen. My body is not the strongest, the leanest or the most muscular body I've ever seen. But it sure as hell can do a whole lot of stuff that it couldn't do a few years, and even a few months ago.
While it's easy to follow the crowd and do a few workouts and exercises here and there, what takes real courage is to stand out from the rest, try something new and really keep at it for a period of time. Get yourself a coach; someone who is qualified to train you. Its our job to make you a fitter, healthier version of yourself. It's very easy to walk into a session and resort to the same old workout; Squats, lunges, leg press, leg extensions, hamstring curls, calf raises. (Am I right??!) However this can only work for a certain period of time. Sooner or later, something has to change; the number of sets, reps, weight, tempo, speed etc. And this is when I often see people giving up. When they've reached a point that they can say, "okay this good enough", until they stop training altogether, revert to square 1 and have to start all over again a few months later. -
Spend time on your body. Invest in it. If a coach or trainer isn't right for you, there's a multitude of information available online. But give your body the time it deserves to build into the best version of itself possible. Your body is the only one you've got!