Facts vs Feelings (and identifying progress vs outcomes)

Coach Sall has been sat on this one a little while and it's a great discussion about where we look for validation and motivation when we're working out.

What data is important? what about how things feel, when we're making a big effort to achieve our goals?

We are often deeply conditioned to believe the number on the scale is indication of our progress (or number of reps that one workout) and we are also pre-programmed to always spot what we failed at. How can we change how we think about data and feelings to encourage us and keep us doing the things that really count?