WIth my first hospital birth I was told to push as soon as I reached 10cm - and I was no where near ready to push. 35 minutes into pushing they mentioned c-section. 40 minutes into pushing my body took over and got the baby out. My pushing was barely accomplishing anything, when my body took over, baby was out within 5 minutes.
WIth my second hospital birth, I dilated quickly and when I reached 10cm I had a slight urge to push. THe OB was still on his way so I was encouraged not to push. I just rested through each contraction and then 20 minutes later announced to everyone that I was pushing NOW, like it or now (my body was). I didn't give much effort at all to the pushes, my body did most of the work and Z was out within 7 minutes (all 9.5 lbs of him).
With my third child, birth center waterbirth, she was in an odd position and the *first* time I had the urge to push I had to actively push and move around to get her into a better position. When she made it past my pubic bone, my body took over and she was born shortly thereafter.
WIth my fourth child, a homebirth, I didn't do any pushing whatsoever - my body did all the work to birth my 10lb 14oz babe! It was 7 minutes from when my body started pushing to when he was in my arms - and few minutes of that was my body taking a break between getting the head out and the rest of the body out! (His labor and birth were completely pain-free.)
It will be interesting to see what happens with this babe - I'm expecting to just relax through contractions, maybe walk a bit, spend lots of the time in water, and let my body do its thing!