There have been many times when things have come about very easily that were God's will for us here. Other matters required much prayer. But nothing has been done because of our "efforts" or minute planning.
The enemy of souls knowns this, and will manuever his slaves into place to make a situation that, on the surface, looks like heavenly intervention.
Satan has studied all of our lives carefully, and knows many triggers to lead us into presuming on God's leadings.
Example: When Lazurus was dying, the disciples were stirred up by their sympathy by Satan to urge Jesus to go rescue him from death. If He listened to them, we would have never raised Lazurus days later from the dead, thus robbing the Gospel Message of much power and proof of His Godhood.
"Pray AND Watch..." is the key. We cannot let our guard down at anytime.