That's how you build the lift. Turning what you think is impossible into actual. As the weight gets really heavy, this becomes ever more important. A lot of it is mental. Anytime I've walked away from an incomplete set in the past I've cursed myself for doing. I now always try to complete even if I fail and I never curse myself for actually trying and failing. It's an amazing thing to push at the boundaries and see progress.
Well done for not giving up on number 4.