Why am I scared of failure?

I did like 40 reps of dumbbell curls. I could have kept going. I learned that burning sensation is not a signal to stop. That you should push till you physically can't perform the action safely.

I never get there. I noticed that if I am in a position where I am asked to give a little more. I don't do it.

I don't like that I can do more but I consistently choose not to. I have been in the same place for the past 12 years. Sure I have done this and that and blah blah. But I am still in the same spot. Working. Staying not fat. Still watching porn. Smoking weed. Pathetic.

Also I am not being too hard on myself. People tend to tell me that. They say I am thriving. Wtf lol. But I think they should raise their standards as well to be honest. I never speak on that because I think if someone is happy with where they are. Who am I to say they shouldnt be? I'm happy for them.