Sometimes you get pulled away from things you want to do, things you feel you need to or even things that must be done. Restarting those tasks can often come with an unhealthy dose of guilt or remorse about the delays and if you let these things weigh you down you can create a vicious cycle of even further delays. So you must learn accept your role in the delay and decide to move past it. Otherwise you will not only have a part in the problem you can actually become the problem itself.
Like anything however if you accept your responsibility in it you can move on and focus on getting it done. Acknowledge, accept and move forward. Like you mean it.