Impossible Goal question

I am working on picking my Impossible Goal for 2020. One idea is to lost weight and get very fit, which I would measure by picking a weight goal and also maybe body fat measurement. My question is what woould worthy fails be? I feel like the problem for me is that I don’t exercise when I should, so that is a lack of doing something and not a worthy failure. Im not sure how worthy fails play into an exercise goal and would love some input.