What's the worst thing that can happen?

When you're young, birthday's are really exciting.  I mean, who cares that Christmas was only a month ago.  It's birthday time!  Presents!  Cake!  My son was excited.  He was counting down the days and moaning with sadness every morning when it still wasn't his birthday. 

Little Man turned 9 on Friday. 
On Thursday evening he came down with a major stomach bug and spent the night being very sick (gross).

But little man soldiered on.  He rested instead of going to school.  I offered to have the family party on Saturday instead of Friday evening so he could feel better but his answer was an emotional "NO!"

His perseverance made me think about characters in our writing.  As writers we're supposed to think of the worst that can happen and then make our characters work through it.  It lends depth and emotion to the story.  It helps readers care for the characters. 

When you're young, what's the worst that can happen on your birthday?  You're too sick to enjoy the presents. 

What's the worst that can happen to your characters in the story you're working on?  Are you challenging your characters enough to make them seem real to your readers?