Most gym rats are “pushers” not “pullers”, and most do too much “horizontal” pushing and not enough “vertical” pushing. If you’re able to press 100-pound dumbbells lying flat on your back, then you should be able to press 70-pound dumbbells overhead for the same number of reps. And for every pushing pattern you do, you should also do the corresponding pulling pattern. For example, a great antagonist for the standing one-arm dumbbell press is the half-kneeling one-arm cable pulldown.
On page 66 of The Elite Trainer, I discuss how pressing strength decreases an average of 2-7% every 15 degrees from a decline, lying position to an upright, seated position. In the example above, you also have to take into account a standing versus a seated position along with the bilateral deficit, but the point is clear: If you have a huge discrepancy between horizontal and vertical pressing strength, your body won’t look or function right and you’re setting yourself up for injury. Likewise, if you prefer having rounded shoulders and a forward head, just keep pushing without pulling!