Warren Wiersbe on how things make you bitter or better

“Our values determine our expectations. If we value comfort more than character, then trials will upset us. If we value the material and physical more than the spiritual, we will not be able to ‘[consider] it all joy!’ If we live only for the present and forget the future, the trials will make us bitter, not better.”
Warren Wiersbe
The Bible Exposition Commentary, 2:338.