I will spare you all my Star Wars nerd knowledge and just focus on one thing that Yoda said to Luke Skywalker that, all pop culture nostalgia aside, is deep with wisdom: "Do or do not. There is no try." Heavy. Let's examine why.
You walk into the gym and see the WOD and it scares you a bit. Instantly your mind starts talking: "You do not know if you can do it. Rather, you know you can do it but you have these expectations in your head. You want to perform so well but the pressure of your expectations is getting to you. I will just try to finish. I will just try to do as much as I can. Then there is that gym over there - look at him being all fit and going unbroken on his workout. How can he do that? I just did five and I feel like death is shaking hands with my air pipe. God the weight feels heavy. My back is starting to hurt just thinking about the 600 murderous reps the coach has programmed. I think he has escaped from some prison for manslaughter and we just don't know yet. I'm getting really tired. I'm not meeting my expectations. This is humiliating. I'm scared I won't finish. I'm just going to stop instead of pushing myself. I will come up with some reason as to why I can't finish. That way I'm not responsible for my poor finish, my poor health, my poor quality of life."
The word try implies that you aren't going to give your 100%. You have already committed to not finishing, to leaving yourself an out, to not taking responsibility for your reps and your effort. When things get uncomfortable you can easily reason that I was just trying and my good isn't enough. By trying you copped out. You will never get better because you never laid it out on the line. Only by doing and failing greatly or succeeding wonderfully are you made into something greater. By testing yourself and letting go of trying do you really succeed. Yoda was right. Do or do not.