My guess is lot of folks simply bend sideways towards the target in an effort to keep weight forward instead of rotating in the backswing. And then reverse the bend in the downswing, causing them to come crashing down on the ball with a steep angle.
Yes, minding first two keys(5S) with a good pivot solves 99 percent of my ills.
Firstly, well done for breaking 90, I am delighted for you. However, I am not sure what breaking 90 actually means, and I will tell you why. The last club I belonged to was a par 74 course, the new one I belong to is a par 67. Needless to say, breaking 90 on my old course was a far bigger achievement than doing it on my new one. Wouldn't it be more logical to say "I was 17 over" ?
I am a rubbish golfer, and have been for eight months. I know what to do, have been able to previously do it, but now find myself gradually getting worse. The crazy thing is that I still enjoy it, because I have the right attitude, and know I am getting older. Fresh air, great company, and the opportunity to stay fit, so what else matters ?