How to Match Flaws to Heroes

A friend of ours, David Farland, often mentions that as the primary reason he thinks people read is so they can watch other people overcoming difficulties in trials and experience it in a sort of safe yet still somewhat threatening way. We fear change and growth is painful but if we can watch somebody else go through it and emerge on top we get a little inner thrill and we feel like we as people can become better people. Let's take this another direction though for people listening who want themselves to be writers how do you match flaws to heroes because I think this is a very important skill to learn. Dan any thoughts?