"You can't see the forest for the trees."

This is another favourite of mine. It's true- by the way. When your walking amongst them, they are just tree's. You have to step back and look at the bigger picture to notice that it's a whole forest you're venturing through. Our eyes fool us.
It's all about perception. Any task that we do has the potential to become a forest. If we started by looking at it as a forest- it would never get done. It's overwhelming. This can be something as big as coordinating a gala event to cleaning your house. You break the job down to little pieces. If you constantly worried about getting the whole house done, you'd get lost.
On the flip side, if you pay too much attention to details, you won't have time for the rest of the project. You're field of view becomes so limited that it boggs you down. You spend all your time focusing on one aspect that you neglect the others.
It's always wise to have a healthy perspective balance. Only looking at things as a forest can hurt you, but focusing on one single tree will do the same damage. My advise is to know what your getting into, keep that idea at the back of your mind, but tackle each obstacle one at a time- giving time to the items that need it.