Martin Luther King Jr. said, "The ultimate measure of a man is not where he stands in moments of comfort and convenience, but where he stands at times of challenge and controversy."
How does this relate to our characters? Our characters should learn and grow over the course of their story. In order to do this, they need challenges. (Real life is like this, too).
Let your mean streak run wild, hold your characters' feet to the fire. What's the worst that could happen in that scene you're writing? Throw a wicked curve ball at your protagonist. What will they do? Will they run and hide? Will they face the challenge? I don't normally advocate meanness and torture (read this previous post about mean girls), but let loose, have some fun tormenting them. Let them show us their character.
A common saying in our community is "I/you can do hard things." When my children complain about a difficult situation, I quote that line to them and remind them that they CAN do hard things. They hate it when I'm right and storm off to do whatever it was they had attempted to avoid. So, make your 'babies' do hard things, in the end, they will thank you.
Write on my friends!