What do golf instructors really mean?

As I've mentioned in other threads I'm giving up on this season which has been frustrating and injury riddled to work on a swing that is technically sound and is built on a good foundation.  Over the last three years I've been told numerous things by golf instructors that have led to my confusion by the apparent contradiction of terms and thought maybe others share in my confusion and frustration so I am creating this thread.

I'll start it out with a few of my favorites;

• Don't grip the club too tightly but not so loose that it's possible to pull out of your hands. Along these same lines, I've heard grip pressure should be a 4 or 5 on a scale to 10.  Grip the club like a tube of toothpaste and hold so that it's tight in your hands but not so tight that it would cause toothpaste to come out of the top.  Maybe I'm slow when it comes to golf, but if I'm holding a full tube of toothpaste with pressure that doesn't cause any toothpaste to come out of the top, then you're going to be able to pull it out of my hands.  There's also the famous grip the club it like you would a bird.
• Grip should be firm but arms and wrists should be loose. Again, if I'm gripping the club tight enough so you can't pull it out of my hands then I'm likely to have some tension in my hands, wrists and forearms.
• Arms and wrists should be loose - Hogan waggle .  I get that, but I've also been told that under ideal swing conditions the club shaft should be perpendicular to the forearms.  On a backswing how does one get the shaft perpendicular to the forearms and maintain that position through the downswing just prior to contact without tightening your forearm and hand muscles?  Conversely they tell you to avoid letting your arms look like wet noodles.

I realize these are supposed to be learned feels but how does one learn the right feel?  Am I the only one that isn't sure what exactly I should "feel"?

Thanks Erik, the thread is not just about grip pressure it's about all the things instructors tell their students which are accurate but can seem contradictory to the student who doesn't know what they should really be feeling.  Other such areas, still head, rear leg flexion, swing hard but don't overswing, take a divot but not too deep a divot, swing your arms faster but don't swing with your arms.

The 5SK did a great job identifying the 5 commonalities that good golfers have but there's a ton of instruction in between that makes it tough for students to know if they are doing something right or not and if they are feeling what they are supposed to or not.

Your friend who's a +3 might have very strong hands so a 5 or 6 to him could be equal to a 8 or 9 for someone else.  I realize that these concepts are difficult to convey, but as a student it is frustrating to always question if you're doing or feeling something the way you should.

Thinking about grip pressure maybe a very bad thing, you grip it like you grip it...if you like to hold on tight too it... do just that. Tension in the swing and at setup comes from not trusting your swing, which comes from lack of practice.