All of us…experience metamorphosis several times during our lives, exchanging one identity for another.
Even after you’re all grown up, your identity isn’t fixed. You may switch careers, change marital status, become a parent, get sick, win the lottery. 
I don’t know if this is stressful for caterpillars, but for humans this can be hell on wheels. 
The best way to minimize trauma is to understand the process. Here are the four phases: