Have you had any troubles or barriers on your experience which have caused you to re-think your ideas?

Question: Have you had any troubles or barriers on your experience which have caused you to re-think your ideas?
- Keywords:
  barrier,
  idea,
  trouble
Asked by Lacey & Mia to Andrei, Dominique, Mark, Masha, Sarah on 17 Nov 2016.
- Mark Catherall answered on 17 Nov 2016:
  
  Yeah, all the time! Often I go into a problem with a certain preconception of how something works, and then halfway through I get surprised and have to re-think everything I thought I knew about it. Those are the best moments, I love being surprised by a solution.

Question: Have you had any troubles or barriers on your experience which have caused you to re-think your ideas?