I've been hearing and reading this question a lot lately and I have a lot of thoughts on it. My first thought is that I never ask this question unless it is something good, not so much 'why me' but 'how did I get to be so lucky'? I think it has a lot to do with expectations and my childhood primed me to expect only negative things. When something happens if it isn't good I accept it and move on. I wonder if the people that ask this were overly blessed when they were younger to only expect to have good things happen.
I truly believe that everything happens toward a purpose. My dad being who he was shaped me into the person I am (for the better in most ways). My having a horrible boss that I could not work for any longer is the reason that I quit and I believe that it was necessary for P and I to get pregnant. It also resulted in other people leaving that company and ending up in better positions in their jobs and home lives. I had an awful roommate in college that would do vengeful things like turn off my alarm clock and lock me out of our dorm room. This resulted in my getting another roommate that turned out to be one of my best friends that is still close to me two decades later. If I look back at anything good that happened in my life, I think I can find something bad that contributed to the good thing that happened. I often cannot see the good resulting at the time and I'm sure that there are many positive things that result that I do not even know about, but I also think it is important to believe (in my case, know) that there is a reason for everything. Hearing this from someone else doesn't necessarily help when you are faced with a challenge, but I believe it is true nonetheless.