Re-examination of beliefs?

Is there any one would re-examined what they believed?
If yes, how did you go about it? And with what end result?

Thanks in advance for the answers.
Update: Ahhh...sorry. Rewording:

is there any one who re-examined what they believed?

And I used 'they' because it is genderless and I avoid being sexist :-P
Update 2: @ KnowGod I understand :-)

@ Kevin Jess thank you as well.
12 answers 12