'times of personal, emotional difficulty enter your life because there is a sin God wants to reveal and root out'
Not true in every case, but in a lot of cases, true.
A lot of the struggles and difficult times that I have come out from have resulted in learning of how many idols I had before God, learning of the pride I had, learning of how much judgement I had.....
One common thing would be this: that I just didn't know I was dwelling in any of these sins until this season of struggle I had to come out of.
Aching, learning, repenting, overcoming. repeat.