Why is it a roller coaster?

I love roller coasters. There is the anticipation of waiting for the ride to start. There is the upps and the downs. There is the feeling of falling. There are times where you are whipped back and forth. Dealing with a loved one who has depression has included all of these elements. But, it has been so worth it. It hasn't been easy but I believe all things happen for a reason and that in the end, I am a stronger person.