When you say you're going to do something and don't do it, you erode self trust. Self trust and following through is something many of us seek but aren't prepared to do. The ego wants to do things that are easy, that it knows how to do and looks for shinier objects to focus on which causes distraction. The distraction leads to not following through on your original intention and then you end up making lame excuses for why you didn't get the original thing done in the first place. Ugh, tiring right?