One of my teachers, Haju Sunim, would often reply to our habitual stories about what kept us from practicing: It is not that you cannot, it is that you do not.
This is both refreshing and humbling.
It is refreshing because if we simply do not do it, then we can easily change that by doing it. There is no impossibility!
It is humbling because it shifts responsibility for our awakening on to us. Why choose delusion?
So whether it is refraining from harming others with our speech or sitting until we fully awaken: it is not that we cannot, it is that we do not.