When I do not do something I said I would do or intended to do, it is only ever* because of lack of willingness, which leads to skewed prioritisation and bad organisation.
I pull myself up short when, on failing to do something, I fall back into the following mental narratives: defending, justifying, explaining, blaming, or expressing good intentions.
If the cause (lack of willingness) is not solved, the failures will continue.
*With extremely rare exceptions