Face it. If you work out with weights, especially if you belong to one of those mirrored funhouse gyms, after a hard set, pumped and sweaty, you check yourself out in one of the said mirrors. This is natural. There is a sensual satisfaction in seeing your body transformed in to one strong and vital by hard work and dedication. Think about this, though: What are you looking at?
Pecs? Check. Shoulders? Check. Abs? Check (well, maybe not). Quads? Check.
All you've done is checked half of your body. The front half. You probably have only worked that half too. That's OK. It's better than nothing.
Most lifters have a pushing strength far exceeding their pulling strength. That's because pushing exercises (dips or bench presses, overhead presses and squats) hit areas that you can see in the mirror. They also react pretty quickly to stimulus and therefore get performed more often. However, these showy beach muscles will cause imbalances and eventually injuries if worked exclusively. You've got to work your back.
You can balance the compound pushing exercises with pulling exercises. Chins and deads qualify as pulls along with one that is rarely done anymore with free weights: the bent row.
The bent row, when executed correctly, will develop all upper and middle back muscles (trapezius middle and lower, latissimus dorsi, rhomboid major and minor ), shoulders (posterior deltoid), biceps (biceps brachii) and to a lesser but noticeable degree your butt (gluteus maximus) and hamstrings (biceps femoris).
To perform the exercise, stand with your feet about shoulder-width apart. Squat about halfway to the bar and bend at the waist. Try to get as close to parallel with the floor as possible. With your back straight it should feel like you are trying to stick your ass in a bucket.
Grab the bar with an overhand grip at roughly shoulder width -- a little wider or narrower won't hurt, but don't be extreme.
Keeping your bent legs and back tensed but relaxed, neck and head in line with your back, pull the bar to your abdomen, touch the bar to your body, and return the bar to the starting position. It is not necessary to put the bar all the way to the floor as in the deadlift. Do not allow the shoulders to round and drop. As with chins, visualize your hands as hooks and concentrate on pulling with your elbows. This will direct the effort to the back instead of the arms.
Perform whatever set and rep scheme you have devised, but quit once you can not touch your body with the bar. By no means yank, bounce or jerk the weight. Concern yourself with steady, mindful work in perfect form or else you'll need someone to tie your shoes for you for the next month.
By adding bent rows to the other compound pulling and pushing exercises, you've got yourself a mighty toolbox with which to build an impressive and balanced physique.
By the way, from personal experience I know an indirect benefit is that the added surface area will hum when someone gives you a hug.