The devil wants to do whatever he can to keep you from praying.
He wants you to think you're too tired, busy or full of doubt to pray.
And if he can't keep you from praying all together, he wants you to be weak in prayer, to think it doesn't work or Gods not listening or he's too far away.
He wants to do anything he can to keep you from the kind of prayer where you know that you can go boldly to God with anything, that ANYTHING you ask for will be done.
And if the devil works so hard to keep us from bold, effective prayer, there must be a reason. And that reason is that when we get connected to God, we really do have the authority to trample on snakes and scorpions, to overcome ALL the power of the enemy.
If the devil knows our authority, so should we. Don't let him keep you from it.
Go boldly to God. Pray without ceasing.