wedge - A piece of material with a thick end that tapers to a thin edge, used to split, support, or secure things; also something that forces separation or division between people or groups.
The disagreement drove a wedge between the two longtime friends, and they really didn't enjoy spending time together anymore.
paradox - A situation or idea that seems strange because it involves two aspects that are very different and seem to contradict each other, and both may be true.
It's a paradox that often it's the busiest people that have to most time to contribute to the needs of others.
