Joseph's dreams first get him into trouble, but his ability to understand them leads him to be chosen by the Pharaoh and to save the world. We could learn a lesson about the mysteries of how the world works. Believers and non-believers can see it as an illustration of the need to keep trying and persevere.
Andrew was impeached because the impeachedment and trial of Andrew Johnson had importent political implications for the balance of federal legislative-executive power.