As one poster said, this really varies according to a person's body structure. Some of us have different shaped collarbones and shoulder girdles. Some of us also have scar tissue from injuries, postural disturbances from being overweight as kids or sitting at computers all day, and some of us have impingement issues already wearing at our rotator cuff.
Behind the neck anything always makes me cringe just because the cervical spine is almost always compressed funky when doing it, not just because of the impingement of the cuff. But I can't sit here and say anyone is wrong or right.
What I can say is that just because you do something a certain way and haven't had an injury yet is not a good indicator of whether or not an exercise is safe for anyone else OR you for that matter. It takes time to erode away at tendons and ligaments. Some of us wake up decades later and wish we never did something a certain way.
So yeah, I'm discussing this more from an injury prevention standpoint rather than a proficiency standpoint.
No matter how you do your shoulders, it would make a huge difference to work with a trainer who understands scapular positioning and have them work with you when you train.
I am as guilty of it as anyone. It is soooooo easy for the scapula to protract or come right out of its natural position during certain parts of any raise or press. When you do this, you risk injury.
I think this is one of the main reasons people find flat bench so unhealthy. It's damn near impossible for people's anterior dominant muscles to be reigned in by their posterior stabilizers during the pressing movement.
If you're wanting maximum size etc, then listen to everyone else, because I don't have anything to share.
If you want to be able to throw a ball when you're 65, without wincing in pain, spend as much time as you can, and exercise as much humility as you can, retraining how you move weights with your shoulders retracted. Spend as much time as you can correcting your posture when sitting at a desk, or driving a car. Take time to learn how the body should be aligned. Get STRAIGHT before you work on getting STRONG. You'll be much happier in the long run.
And for many of us, there is most likely a lot of scar tissue that is built up over the years from misuse or from injecting AAS into our delts. Make sure you are doing corrective exercises and breaking down that tissue as much as possible so that you can retain natural movement. An overhead press with adhesions in your delts will cause some serious disturbances in movement patterns.
SUCK UP YOUR CROSSFIT HATE FOR A SEC > This could save your shoulder's lives...
Scapular Mobility | Feat. Kelly Starrett | MobilityWOD - YouTube
Kelly has a ton of videos that will help you understand how to move properly, so you can lift forever.
I could make a million comments, but look at 2:10 to notice how he corrects the arm floating too far away from the ear. Notice how much you might want to move your arm away from your ear when doing this kind of fascia manipulation...