We are all walking contradictions.
We say something and then we do something else.
It brings the challenge that at some point you are not even trusting yourself. You say things and you know that you will not be able to live up to it.
I realize that it is important that I do what I say and that I am very realistic with myself. If I want to complete my aquarium stand, I have to be realistic with when and how I will do it. I need to be realistic with my time and my abilities so that I am telling myself the truth. I will trust myself and will sound more confident when I tell my life partner that this is what I am doing.
There is also the fact that people remember your contradictions a lot more than when you have simply stated the facts.