Look at these sample answers:

• For me, when decisions present themselves, I have no problem taking responsibility.

• Turning down a job that paid very well but did not interest me very much.

• A very personal decision, but I was able to settle it.

• How best to approach you to set up this interview!

• There is no such thing as a difficult decision when you have thoroughly analyzed the situation. 

• (Mention a decision and show how you managed to solve the problem.)