I think that many beliefs gets us stuck. Sometimes we demand too much of ourselves, sometimes it's just fright of anything. Also depends on how you were raised, were you sheltered etc.
A lot of us just lack experience in life, I think. Usually, experience gives you courage, because the thing you get to know is not unfamiliar and scary anymore.
1) not sure
2) it's good to know where you are heading with your experience. I started doing "don't break the chain" thing and tracking how much time I spend on that certain thing each day. So as to finally see how much it is done in, lets say, month. Because on my level of knowledge and experience, I have no sense of how much I've done in how long exactly. So it can be one of the things that can make you inpatient or scared that you are not advancing. I know that some people don't track such things, because they already work with passion and courage, and need no proof they worked hard. I realized I need a proof.
3)At first, I didn't like sharing my goals with anyone, but I shared some recently, and it's not that scary.It's true that expectations are automatically there once you share it, and I'm not a fan of doing such thing to merely boost productiveness, but I guess, do what works for you. I personally didn't do it to push myself to be productive, but to gain understanding from other party, and to take responsibility for what is mine.
Right now I'm still a wimp, but I'm on a good way to improve and become more disciplined.
I am somewhat spoiled, used to comfort, used to delaying when things get harder. I know this because I tasted disciplined life before, and honestly, I miss it. It is hard to rewire now, but I know it's something I need to develop over time,bit by bit.
We often look at people that succeeded and never see TRUE story behind it. One thing is to read "he ran every day for 5 miles", but the other thing is to know the feeling of running that much every day. We feel the urge to have it all now, looking at end result, without looking at the process. And the process is hard work and discipline mostly. That's why some give up, deflating like souffle after first failure.
This is just my viewpoint, gathered only from what I'm like and my friends and family. Can't say for other people. Looking forward to other answers,just to see how other people experience productiveness and un-productiveness .