Perspective.
Read this, it has a lot of points you will understand about wisdom.
http://en.wikipedia.org/wiki/Perspective_(psychological)
What you happen to you if you were made the teacher of your class the rest of the year? And the students wanted to goof off, and do no reading?
Justice warren agreed with Justice Frankfurter that being on the court changes a person's views. Why do you think that often happens?
2 answers
Where else does a person see such a huge variety of people and their problems? Also, determining the Constitutionality of complex issues must change the judge's views.