God's will?

Instead of diligently chipping away at my theology homework on Christian Doctrine, Shirley C. Guthrie's chapters on the "person" of God and why we exist, I cannot stop contemplating the ambiguity of God's will.
I've always heard and believed that one of the ways to know God's will is by the ominous "opening of doors." And, quite truthfully, I've followed most of the opened doors, assuming that they are God's will. If everything works out perfectly and it feels right, it is... right?
On Sunday, I was listening to a podcast of The Village church in Dallas where the speaker Beau Hughes began a series on Jonah. To my surprise and discomfort (the good kind), he revealed that there will always be "open doors" leading away from God and His plan. In fact, there will probably be several appealing options, pretty ornamented doors with signs that say OPEN ME on them. Pretty colored doors with gold handles. Doors that swing open noiselessly and easily. For Jonah, there was a boat going to Tarshish.
I can't help but wonder how many luxurious cruises I've taken to Tarshish, missing the one to Nineveh.
Thankfully, I haven't been swallowed by a great sea creature- yet.