****ing hell mate, the thread is Spurlock's gym, what kind of example is that to set?
Seriously though, if you're waiting to feel 100% ready, it'll never come, there'll always be something putting you off, because you don't get the 'addiction' if you like, until you start seeing results. The first few are ****, then they get easier.
I always focus on the hardest things to do, such as dips, pull ups, deadlifts, squats... the way I see it, once I can do them, then I can do everything.
I remember attempting dips for the first time, I think I got about 1.5 reps out, it was embarrassing. Pull ups I couldn't do any, so had to start with a resistance band for assistance... then one day you can do 3 sets of 10 unassisted and it feels great.