Man is fatally slow on the uptake; it always takes him until the next generation to understand what's going on.
The exit is usually where the entrance was.
He who wants to get to the source must swim against the current.
Do not turn your back on anyone. You may be painted on one side only.
When you jump for joy, beware that no one moves the ground from beneath your feet.
The window to the world can be covered by a newspaper.